Technical Manual for the Use of Recycled Materials Generated by

Transcription

Technical Manual for the Use of Recycled Materials
Generated by Other Industries in Construction
Projects
July 2005
Public Works Research
Institute
FOREWORD
The amount of waste generated by public works and other construction projects
reaches 83 million tons every year, and the amount of waste that is processed through
reduction and reuse at final disposal sites is 6.64 million tons (8%). Moreover, the amount of
general waste generated by domestic households and offices on an annual basis is 55 million
tons, and 11 million tons (20%) of this is subject to final disposal. The annual amount of
industrial waste (excluding waste generated by the mining industry) is 235.8 million tons,
and 11.79 million tons (5%) of this is subject to final disposal. Although the amount of general
waste is smaller than that generated by the construction industry, the amount from the
former source that is subject to final disposal is higher. Despite the fact that the percentage of
industrial waste subject to final disposal is relatively small, the amount of waste generated is
four times greater than the amount of construction waste, which means that the amount of
industrial waste treated at final disposal sites is twice as much as that of construction waste.
Amidst this background of waste generation and processing capabilities, the fact of
the matter is that final disposal plants are reaching their limits, and this is turning into a
social problem. It is a general principle that the person or organization responsible for the
generation of construction waste, general waste, or industrial waste is also responsible for
reducing the amount of final disposal by reducing and recycling the waste. Therefore, some
say that if we conform to this principle there is no necessity for anybody other than the person
responsible for the waste to approach the issue of reuse in a positive manner. However,
looking at this problem from the wider viewpoint, there is also a contrary concept that all
waste should be effectively reused and that recycled materials should be accepted as widely as
possible, by all industrial fields, in a manner that transcends industrial demarcation lines.
Considering the fact that Japan is currently aiming at creating a circulatory society and
publicness of civil engineering works, it has become inevitable for the construction industry to
make a contribution to society in the field of waste recycling. In addition to this, the effective
use of recycled waste will act as a substitute for the materials that are conventionally
purchased new, and by adopting a policy such as this we will be able to reduce the cost of
materials, save energy and help conserve resources. This will also lead to the possibility of
reducing costs for companies, even though they will have to pay for the recycled materials.
However, in many cases, many points need to be considered for the effective use of recycled
materials, which should not be considered new materials. Therefore, it is crucial to make use
of the recycled materials while paying due attention to their efficacy and influence.
To create a wide range of technical menus for the purpose of reusing conventional
ii
waste, and to expand the areas where this waste is used, the Public Works Research Institute
has conducted a vast number of research projects on the waste generated outside the
construction industry, such as general waste and industrial waste. Some of the results that we
have achieved have already been compiled in the “Manual for Evaluating Recycled Resources
Generated by Other Industries for Test Facilities in Public Works Projects” (Public Works
Research Institute Document 3667, September 1999). In addition to adding new details on the
research and development results achieved both within and outside the Public Works
Research Institute after the publication of the above-mentioned manual, this manual also
includes new areas that rely on positive acceptance of the use of recycled waste materials
generated by industries outside the construction industry as a basic prerequisite.
I sincerely wish that this manual will serve the purpose of contributing greatly to
Japanese society by encouraging the construction industry to make effective use of waste
materials in public works projects.
Tadahiko Sakamoto, Chief Executive
Public Works Research Institute
iii
COMMITTEE FOR THE INVESTIGATION OF TECHNOLOGIES FOR REUSING RECYCLED
WASTE GENERERATED BY OTHER INDUSTRIES
Committee Members
Chairman:
Yukikazu Tsuji, Professor, Department of Civil Engineering, Faculty of
Engineering, Gunma University
Member:
Hiroshi Ito, General Supervisor, Department of Building Materials and
Components, Building Research Institute
Member:
Mikio Kobayashi, Research Group Leader, Advanced Recycling Technology
Research Group, Research Institute for Environmental Management
Technology, the National Institute of Advanced Industrial Science and
Technology
Member:
Hiroaki Shiraishi, Director, Research Center for Environmental Risk,
National Institute for Environmental Studies
Member:
Masahiko Matsue, General Manager, Landscape and Ecology Division,
Ministry of Land, Infrastructure and Transport, National Institute for Land
and Infrastructure Management
Member:
Hiroshi Miki, General Researcher, Technology Research Department, Public
Works Research Institute
Member:
Takeshi Kinoshita, Chief Researcher, Construction Technology Team,
Technology Promotion Department, Public Works Research Institute
Member:
Hiroshi Watanabe, Chief Researcher, Structure Management Technology
Team, Technology Promotion Department, Public Works Research Institute
Secretary:
Hirotaka Kawano, Group Leader, Material and Geotechnical Engineering
Research Group, Public Works Research Institute
Steward:
Seishi Meiarashi, Senior Researcher, Special Research Project, Material and
Geotechnical Engineering Research Group, Public Works Research Institute
Steward:
Itaru Nishizaki, Senior Researcher, Advanced Materials Research Team,
Material and Geotechnical Engineering Research Group, Public Works
Research Institute
Steward:
Masaaki Ozaki, Senior Researcher, Recycling Research Team, Material and
Geotechnical Engineering Research Group, Public Works Research Institute
Steward:
Hidetoshi Kobashi, Senior Researcher of the Soil Mechanics Research Team,
Material and Geotechnical Engineering Research Group, Public Works
iv
Research Institute
Observers:
Shigetoshi Kobayashi, Board Director, Public Works Research Center
Hiroyuki Sakamoto, Expert Assistant to the Director, Public Works
Research Center
Secretariat:
Sekiko Arakawa, Chief, Planning and Auditing Division, Public Works
Research Center
Junji Asami, Assistant Chief, Planning and Auditing Division, Public Works
Research Center
v
Contents
CHAPTER ONE. COMMON ELEMENTS
1. Overview
1.1 Objectives
1.2 Range of Application
2. Quality and Usage of Recycled Materials
2.1 Quality
2.2 Environmental Safety Factors
3. Manual Configuration
3.1 Contents of the Manual
3.2 Annotation Conventions
4. Terminology, Definitions, and Explanations
CHAPTER TWO. TECHNOLOGY UTILIZATION MANUAL
1. General Waste Incineration Ash
1.1 Solubilization and Solidification Processes
1.1.1 Pavement Subgrade Materials
1.1.2 Aggregate for Asphalt Paving Surface Binder Courses
1.1.3 Aggregate for Cast-in-Situ Concrete
1.1.4 Aggregate for Factory-Produced Concrete Products
1.1.5
Backfill
1.2 Calcination Processing (Process for Making Cement)
1.2.1 Concrete Poured On-Site
1.2.2 Factory-Produced Concrete
2. Sewage Sludge
2.1.1 Pavement Subgrade Materials
2.1.2 Aggregate for Asphalt Paving Surface Binder Courses
2.1.3 Aggregate for Cast-in-Situ Concrete
2.1.4 Aggregate for Factory-Produced Concrete Products
2.1.5 Backfill
3. Coal Ash
3.1 Cement Mixture Solidification
3.1.1 Embankment Fill and Artificial Foundation Materials
3.1.2 Subgrade Materials
3.2 Coal Admixture Solidification
vi
3.2.1 Subgrade Materials
3.3 Sintering and Calcination Processing
3.3.1 Artificial Aggregate
3.4 Crushing Processing
3.4.1 Filler for Asphalt Pavement
4. Waste Wood
4.1 Shredding Processing
4.1.1 Mulching and Cushioning Materials
4.1.2 Pedestrian Paving
4.1.3 Tree-planting Foundation Materials
4.1.3-1 Raw Chip Tree-planting Foundation Materials
4.1.3-2 Compost Tree-planting Foundation Materials
5. Waste Glass
5.1 Pulverization Processing
5.1.1 Paving Road-bed Materials
5.2 Pulverization Calcination Processing
5.2.1 Tile Blocks
5.3 Fusion and Foaming
5.3.1 Embankment Fill Materials
CHAPTER THREE. TEST FACILITY MANUAL
1.1 Sintering and Calcination Solidification Processing
1.1.1
Paving Road-Bed Materials
2. Sewage Sludge
2.1 Sintering and Calcination Solidification Processing
2.1.1 Tiles and Other Calcinated Products
2.2 Incineration Ash and Coal Ash Admixture Solidification
2.2.1 Soil Quality Improvement Materials
2.2.2 Road-Bed Materials
3. Coal Ash
3.1.1 Filler for Asphalt Paving
3.2 Hydrothermal Solidification
3.2.1 Asphalt Paving
3.3 Use by Category
3.3.1 Admixture Materials for Concrete
vii
3.3.2 Road-bed Materials
3.3.3 Road Foundation Materials
3.3.4 Enbankment Fill Materials
3.3.5 Filler Materials
3.3.6 Backing Materials
3.3.7 Soil Quality Improvement Materials
4. Waste Glass
4.1.1 Aggregate for Asphalt Paving Surfaces
4.1.2 Aggregate for Resin-based Paving Surfaces
4.1.3 Aggregate for Interlocking Blocks
4.2.1 Tree-planting Water Retention Materials
4.2.2 Spring Water Processing Materials
4.2.3 Foundation Improvement Materials
4.2.4 Lightweight Aggregate
5. Waste Rubber (Waste Tires)
5.1 Pulverization and Recycling Processing
5.1.1 Aggregate for Asphalt Paving
5.1.1-1 Freeze-suppression Paving
5.1.1-2 Perforated Rubber Paving
5.1.1-3 Pedestrian Rubber Paving
5.1.1-4 Pedestrian Rubber Block Paving
6. Waste Paper
6.1 Shredding and Thermal Pressure Processing
6.1.1 Concrete Mold Frames
7.Waste Wood
7.1 Carbonization
7.1.1 Soil Improvement Materials
7.1.2 Earth Retaining Materials for Bank Protection
7.2 Wood Meal + Plastic
7.2.1 Mold Frame Materials
7.2.2 Civil Engineering Materials
CHAPTER FOUR. MATERIALS REQUIRING FUTURE INVESTIGATION
1. Coal Ash
1.1 Solubilization and Solidification
viii
2. Waste Roofing Tiles and Ceramics
3. Seashells
4. Waste Plastics
4.1 Pulverization and Recycling Processing
4.1.1 Improvement Materials for Asphalt Paving
4.1.3 Factory-produced Plastics (Fake Wood, Stakes, Etc.)
5. Recycled Materials Not Mentioned
APPENDIX
1. Environmental Quality Standards for Soil Pollution
Appendix
Addendum
2. Regulations for Implementing the Soil Pollution Prevention Law
Appendix #3 (Related to Article 3, Clause 3)
3. Department of the Environment 19th Announcement
Appendix
Addendum
4. Standard Values for Evaluating Environmental Risks
ix
Chapter One—Common Elements
x
1. Overview
1.1 Objectives
Owing to continued promotion of the effective use of resources and
environmental conservation in recent years, there is a need for positive
efforts to be made to use recycled materials generated by other industries in
public works construction projects.
This manual was compiled by engineers engaged in encouraging
construction projects to use recycled materials generated by other industries.
It is intended as a guidebook to provide information on the quality testing
and evaluation of recycled materials, and on the technologies that can be
used for these purposes.
Before the recycled materials generated by other industries can be
used in public works projects, they need to have the correct physical and
chemical properties for the jobs they are to be assigned, and they must be
environmentally friendly. It is also necessary for materials that need to be
reused repeatedly, such as asphalt admixtures used for paving, to have the
additional capability of repeated usage. This manual therefore lays out the
tests and evaluation methods for examining all relevant aspects of these
various requirements.
There are many cases in which there is a lack of sufficient technical
information with regard to research into the development and use of recycled
materials, such as information on the long-term durability of materials, for
example. The details provided within this manual therefore place priority on
recycled materials for which results have been accumulated during use and
for which comparatively few problems have been recorded.
In order to clarify the recycled materials that are covered within this
manual, details on the definitions of waste are provided in Fig. 1-1, details on
the types of industrial waste (by-products) and the locations in which they
appear in this manual are provided in Table 1-1, and details on the
relationship between industrial waste types (by-products) and construction
waste are provided in Fig. 1-2.
Waste
Industrial Waste (20 types)
Garbage, bulky waste, cinders,
Waste materials produced by
sludge, excreta, waste oil, waste acid,
business activities that are stipulated
waste alkali, animal corpses and other
by the law.
2
unwanted materials.
General Waste
(Solid and liquid wastes; vapor wastes
excluded.)
Wastes other than industrial waste.
Fig. 1-1. Types and Classification of Waste (Outline)
Table 1-1. Examples of Industrial Waste (including Construction Waste)
and Locations in this Manual
Type
(1) Cinders
Detailed Examples (Items in boxes
Location in this Manual
include construction waste)
Coal dust, coke ash, heavy oil ash,
Chapter 2, Coal Ash
residual incineration ash from
Chapter 3, Coal Ash
activated industrial waste, residue
from furnace cleaning
(2) Sludge
Factory waste water and other
Chapter 2, 2. Sewage
processed sludge, sludge generated
Sludge
during manufacturing processes by
various manufacturers, bentonite
Sludge
sludge and other construction sludge,
mixed concrete residue, sewage
sludge, sludge from water purification
plants
Waste lubricant, waste cleaning oil,
(3) Waste Oil
waste cutting oil, waste fuel, waste
―
cooking oil, waste solvent, tar pitch
Waste sulfuric acid, waste
hydrochloric acid, waste nitric acid,
(4) Waste Acid
―
waste chromic acid, waste iron
chloride, waste organic acid, other
liquid acids generated in acid cleaning
and other processes
Waste liquid solution, waste
(5) Waste Alkali
photographic developing fluids, other
alkaline liquids generated in alkaline
3
―
cleaning and other processes.
Synthetic resin waste, synthetic
(6) Waste Plastics
Chapter 4, 4. Waste
fiber waste, synthetic rubber waste,
Plastics
etc.,
Chapter 3, 5. Waste
synthetic polymer waste,
waste tires (synthetic rubber),
Rubber (Waste Tires)
ion-exchange resin waste, etc.
Paper used in construction projects, Chapter 3, 6. Waste
pulp, paper, and paper used in paper Paper
(7) Waste Paper
processing plants, newspaper
industry, publishing industry, and
printing and processing industry.
Wood used in construction projects,
timber and wood used by wooden
(8) Waste Wood
Chapter 2, 4. Waste
Wood
product manufacturers (including the Chapter 3, 7. Waste
furniture industry,) and wood used in
Wood
the pulp manufacturing industry and
the wholesale timber import industry.
Fabric used in construction projects,
fabric manufacturing industry
(9) Waste Fabric
―
(excluding the apparel industry and
other fabric product manufacturing
industries).
Chapter 2, 1. General
Solid and unwanted fermentation
Waste Incineration Ash
residue from animals and plants:
Chapter 3, 1. General
(10) Animal and
brewery residue, rice bran, wheat
Waste Incineration Ash
Plant Residues
bran, bean curd residue, coffee
grounds, waste ham, manufacturing
Sludge
residues, raw material residues
Sludge
Livestock slaughtered or butchered at Chapter 4, 3. Seashells
(11) Solid Animal
slaughterhouses, solid and unwanted
Remains
poultry processed at
poultry-processing plants.
4
(12) Waste Rubber
(13) Metallic Waste
Natural rubber waste
Waste metal shavings, waste
Chapter 3, 5. Waste
Rubber (Waste Tires)
−
polishing residue, empty cans, scrap
Chapter 2, 5. Waste
Glass
(14) Waste Glass,
Waste Concrete,
Waste glass, waste fire-resistant
bricks, waste ceramics, cement
and Waste Ceramics manufacturing residue
Chapter 3, 4. Waste
Glass
Chapter 4, 2. Roofing
Tiles and Waste
Ceramics
Slag from blast furnaces, rotary
(15) Slag
―
kilns, and electrical furnaces; cupola
slag, foundry waste, impure ores
Concrete debris (cement, asphalt,)
(16) Debris
brick debris, roofing tile debris, and
―
other non-combustibles.
(17) Animal Excreta
(18) Animal Corpses
Excreta from the agricultural livestock
―
industry
Animal corpses from the agricultural
―
livestock industry
Waste collected by particulate
(19) Particulate
collection facilities (dry and wet) and
Waste
generated by ash-generating facilities
(Dust)
as stipulated in the Air Pollution
―
Control Law.
(20) Waste treated
for disposal
Industrial or imported waste listed in
(Waste Materials
(1) to (19), which has been processed
regulated in
for disposal, except for waste
Government
generated by navigation and portable
Ordinance Clause
waste.
13, Article 2)
5
―
Fig. 1-2. Industrial Waste and Construction Waste
(Source: Ministry of Land, Infrastructure, and Transport Homepage)
1.2 Range of Application
This manual applies to the use of recycled materials generated by
industries other than the construction industry in construction projects.
The levels of environmental safety for the recycled materials described
in this manual are regulated in consideration of the new trends in the
revisions to environmental standards and other factors. For quality factors
other than environmental safety, the same levels as for ordinary materials are
required. However, for some recycled materials for which the same level or
higher is difficult to attain, high quality levels are not required. Instead, usage
and application scopes suitable for the recycled materials are applied here.
This manual has been designed to promote the use, in construction
projects, of those recycled materials whose methods of use remain unclear.
Consequently, materials for which quality standards have already been
stipulated through governmental ordinance or construction technology
6
inspection certificates—such as fly ash or blast furnace slag used as additives
in concrete—have been omitted from the manual as a general policy. Lists of
the recycled materials that have been omitted from this manual and that may
be used for general purposes are shown in Table 1-3 and Table 1.4.
Note that the use of composted sludge, dried sludge, and digested or
dehydrated sludge included in sewage sludge as nutrients for improving soils,
or as fertilizers for urban greening, has already been covered in the Guidelines
１）
and is consequently omitted here.
Table 1-3. Recycled Materials Covered by JIS
JIS Product Name
Waste Product Name
Application
Recycled reinforcing bar
Waste steel
Reinforcing bar
Blast furnace cement
Slag (blast furnace
Cement for concrete
Fly ash cement
slag)
Coal ash (fly ash)
Fly ash
Coal ash (fly ash)
Additive for concrete
Subgrade asphalt filler
Fine blast furnace slag
dust
Blast furnace slag
aggregate
Electric furnace oxidizing
slag aggregate
Iron and steel slag for
Slag (blast furnace
Additive for concrete
slag)
Slag (blast furnace
Aggregate for concrete
slag)
Slag (steel slag)
Subgrade material
Slag (blast furnace
slag)
roadways
Ferronickel slag aggregate
Slag (nickel slag)
Aggregate for use in
concrete, road-bed
material
Copper slag aggregate
Slag (copper slag)
Aggregate for use in
concrete, road-bed
material
Recycled plastic bars,
Waste plastic
7
Bars, stakes, plates,
stakes, plates
signposts
Recycled plastic signposts
Rubber crumb
Waste rubber (waste
vulcanized rubber)
Blocks, elastic paving
material
Table 1-4. Recycled Materials Awarded Construction Technology Inspection
Certificates
Waste
Resource [Product Name]
Certificate Holder
Application
(Inspection Org.)*
Coal Ash
Classified fly ash [Fine Ash]
Sumitomo Osaka
Admixture for
Cement, others
concrete
(PWRI)
Coal Ash
Road-bed, road foundation,
Mitsui Mining Co.
Road-bed, road
embankment filler [Pozotec]
Ltd. (PWRI)
foundation,
embankment
filler
Coal Ash
Substratum road-bed material
[Ash Roban]
Chubu Electric
Subgrade
Power Co., Inc.
material,
(PWRI)
road-bed
material
Coal Ash
Lightweight foundation
Okinawa Electric
Embankment
material [Ganjodo Hasai-zai]
Power Co., Inc.
filler, subgrade,
(PWRI)
backfilling
material
Coal Ash
Synthetic foundation material
[Core Soil Q]
Kyushu Electric
Embankment
Power Co., Ltd.
filler, subgrade,
(PWRI)
back-filling
material
Coal Ash
Artificial foundation material
[Zett Sand]
Ube Industries, Ltd., Embankment
others (PWRI)
filler, backing,
backfill
Coal Ash
Particulate foundation
Shikoku Electric
material [Hai-Tech Beads]
Power Co., Inc.
8
Subgrade,
road-bed
(PWRI)
material,
backfilling
material
Coal Ash
Drain construction [Resoil
Chubu Electric
Drainage
Generated
Koho]
Power Co., Inc.,
material
Soil
others (JICE)
Generated
Particulate soil [TG Phoenix
Soil
Soil]
Generated
Sub-base course material
Soil
Waste
Paper and
Tokyo Gas Co., Ltd.
Backfilling soil
(PWRI)
Daiko Group, others
Sub-base course
(PWRI)
material
Alternative plywood mold
Sanwa Group
Molds
[Eco-Pal Panel]
(PWRI)
Foundation consolidation
Taiheiyo Cement
Foundation
material [Geoset Eco]
Corporation (PWRI)
consolidation
[Polinite]
Fabric
Incinerator
Ash
material
Waste
Vegetation base [New Nekko
Kumagai Gumi Co.,
Wood
Chip Koho]
Ltd., others
Vegetation base
(ACTEC)
Waste
Vegetation base [W Chip
Raito Kogyo Co.,
Wood
Koho]
Ltd. (PWRI)
Waste
Vegetation base [Root
Nishimatsu
Wood
Recycling Koho]
Construction Co.,
Vegetation base
Vegetation base
Ltd. (ACTEC)
Waste
Plastic
Bag material for foundation
consolidation [Eco-Sank-Net]
SDK Co., Ltd.,
Consolidation of
others (PWRI)
foundations,
bank protection,
groynes
Waste
Bag material for consolidation
Kyowa Co., Ltd.
Consolidation of
Plastic
of foundations [Kyowa Filter
(PWRI)
foundations,
Unit Eco-Green]
bank protection,
groynes
Waste
Bag material for foundation
Maeda Kosen Co.,
Consolidation of
Plastic
consolidation [Bottle Unit]
Ltd., others (PWRI)
foundations,
bank protection,
groynes
9
Waste
Lightweight foundation
Kishimoto
Lightweight
Glass
material [Super Sol]
International
foundation
Technology
material
Research Institute,
others (PWRI)
Steel Slag
Material for compaction
Taisei Corporation,
Foundation
[TAFDEX]
others (PWRI)
compaction
material
* (JICE): Japan Institute of Construction Engineering; (PWRI) Public Works Research
Institute; (ACTEC): Advanced Construction Technology Center. Manuals and other
documentation for use of recycled materials for which construction technology inspections
and certificates have been issued are listed in the technology inspection reports. The
technology inspection report can be obtained from the company that received the inspection
and from the relevant inspection organization.
Although many recycled materials are used in public works projects
in accordance with the stipulations laid down in the Law on Promoting
Green Purchasing, these are selected from the resources for which usage
methods have already been clarified, such as JIS products. Therefore, these
products are omitted from this manual. For reference, a list of the resources
purchased for use in public works projects in fiscal year 2003, together with
the amounts used, is shown in Table 1-5.
Table 1-5. Results of Green Purchasing Activities in Public Works Projects
(Fiscal Year 2003) (Source: Ministry of Land, Infrastructure, and Transport
Homepage)
No.
１
Product
Unit
(Product Classification)
(Product Name)
Embankment filler, etc.
Processed soil recycled from
Volume
Used
㎥
91,316
construction sludge
Granulated blast furnace slag ㎥
２
199,842
for use in earthworks
３
Concrete blocks, asphalt
Recycled hot asphalt mixture
T
3,709,355
Asphalt mixture containing
T
10,796
concrete blocks, recycled
materials
４
Asphalt mixtures
iron slag
10
５
Slag aggregates for use in
Blast furnace slag aggregate
㎥
24,451
６
concrete
Ferronickel slag aggregate
㎥
6,425
Copper slag aggregate
㎥
7
Recycled aggregate, etc.
㎥
3,637,576
Subgrade material mixed
㎥
115,775
７
８
Concrete blocks, recycled
materials
９
Subgrade materials
with iron and steel slag
10
Small-diameter logs
Thinned wood
㎥
4,412
11
Blended cement
Blast furnace cement
t
259,236
12
Fly ash cement
t
130,430
13
Ready-mixed concrete (blast
㎥
5,120,508
㎥
17,647
furnace)
14
Ready-mixed concrete (fly
ash)
15
Concrete, secondary concrete
Permeable concrete
㎥
3,496
16
products
Secondary permeable
qt
531,418
Undercoat (heavy-duty)
㎏
139,378
Low-volatility organic
㎡
909,405
solvents
㎏
703
Bark compost
㎏
1,683,435
Sludge fermented compost
㎏
749,151
qt
13,722
concrete products
17
Paint
18
Water-based paints for road
marking
19
Gardening materials
20
made of sewage sludge
21
Street lighting
Environmentally friendly
street lighting
22
Tiles
Ceramic tiles
㎡
43,190
23
Construction equipment
Insulating metal sash
-
66
Particle boards
㎡
129
25
Fiber boards
㎡
1,520
26
Wood cement boards
㎡
6,505
windows and doors
24
Recycled wooden boards
27
Insulating materials
Insulating materials
-
229
28
Lighting equipment
Lighting control systems
-
157
11
2. Quality and Usage of Recycled Materials
To start using recycled materials generated by other industries, it is
necessary to satisfy various conditions, such as quality, environmental safety,
economic viability, and supplies that meet demands. Considerations towards
quality and environmental safety are listed below.
2.1 Quality
To ensure the use of recycled materials generated by other industries,
it is crucial that the materials meet levels of quality that satisfy the
requirements at the site where they are to be used.
The quality examinations outlined in this manual for recycled
materials that have not been quality regulated conform to existing quality
standards and test methods used to regulate new materials. However, as
there are very few recycled materials that have the same characteristics of
new products, there are certain items for which new quality regulations have
been established, such as the regulations for recycled aggregate used in
construction by-product concrete, which differ from the quality regulations
stipulated for aggregates used in new products. Regardless of whether the
quality regulations established for new products or the quality regulations
established for recycled materials are applied, it is expected that site
engineers will carefully examine and record all details on the materials, and
then select the most rational and economically viable materials for practical
usage.
2.2 Environmental Safety Factors
(1) Evaluation Standards and Test Methods
There are two standards for evaluating the environmental safety
levels of recycled materials; evaluations based on toxic effluents, and
evaluations based on toxic content. The “Environmental Quality Standards
for Soil Pollution” (Ministry of the Environment Report 46, August 23 1991)
are available as standards for regulating toxic effluents, and these stipulate
the regulated toxic effluent values and test methods for 25 types of toxic
12
substances. These standards were revised in 2001 to add fluorine and boron,
making a total of 27 effluents that are currently regulated. Also, Clauses 1
and 2 in Article 18 of the “Enforcement Regulation of the Soil
Contamination Countermeasures Law” (Ministry of the Environment Law
No. 29, enacted on December 26 2002) include similar regulations. The only
difference between them is that the latter does not include a standard on
copper effluent from rice paddies.
Meanwhile, as standards regulating the content of toxic substances, Clauses
2 and 3 of Article 18 of the “Enforcement Regulations of the Soil
Contamination Countermeasures Law” describes the standardized limits of
the contents of nine types of toxic substances in soil.
Therefore, the environmental safety standards for the recycled
materials in this manual principally satisfy both the effluent and content
values of toxic substances.
The Ministry of Health, Labor, and Welfare stipulated the maximum
limits of toxic effluents of six substances—cadmium, lead, hexivalent
chromium, arsenic, total mercury, and selenium—in molten slag solidified at
1,200 degrees C or higher in their notification regarding the use of recycled
incinerated molten slag generated from general waste (“On Promotion of the
Reuse of Solidified Molten General Waste”, March 26 1998, Ministerial
Announcement No. 508, Environmental Health Division, Health Service
Bureau, Ministry of Health, Labor, and Welfare) This also advocates the
concept that substances other than molten slag must satisfy the conditions
stipulated in the Environmental Quality Standards for Soil Pollution.
With regard to slag melted at 1,200 degrees C, therefore, this manual
has adopted the effluent standards for the six substances listed in the
Ministry of Health, Labor, and Welfare’s standards for solidified molten
substances, as well as the toxic content standards for the six toxic substances
in molten slag listed in Clauses 2 and 3 of Article 18 of the “Enforcement
Regulations of the Soil Contamination Countermeasures Law”, to meet
environmental safety standards by conforming to these standards.
13
We have therefore decided to apply effluent standards for 26 of 27
types of substances set out in the “Environmental Quality Standards for Soil
Pollution” (hereinafter referred to as the “effluent standards”), with the
exception of copper in rice paddies. We have also decided to apply the content
standards for nine toxic substances laid down in Clauses 2 and 3 of Article 18
of the “Enforcement Regulations of the Soil Contamination
Countermeasures Law” (hereinafter referred to as the “content standards”)
for organic materials (wood waste, waste tires, waste plastic, etc.,) and
recycled materials that are sintered for processing, and we will check the
concentrations of these toxic substances as needed. Here, the 26 types of
effluent standards are the same as those set up in Clauses 1 and 2 of Article
18 of the “Soil Contamination Countermeasures Law”.
(2) Test Frequency
Tests on toxic effluents and toxic content are carried out periodically
to verify conformity. The frequency of these tests is not predetermined and is
therefore a topic for future consideration. However, we worked on a standard
for verifying the safety of such substances in recycled materials by conducting
tests to check the effluent amount and the content of toxic substances once per
lot and at least four times a year during the use of the recycled materials.
During a period of approximately one year prior to usage, manufacturers are
obliged to submit the results of tests on toxic effluents and toxic content.
(3) Period for Evaluating Recycled Materials during Usage
It is desirable to verify the environmental safety of the recycled
materials before they are used and as early as possible in the distribution or
usage processes. If the safety of the products (mixtures, etc.) has already been
verified, there is no need to carry out additional inspections. In the case of
products for which verification of the raw substances is impossible (as in the
manufacture of concrete products containing incineration ash; environmental
safety test reports do not exist for such sintered products), tests must be
conducted on both the solid cement mortar and the products manufactured in
the factory. In this case, the conditions of application are restricted in
consideration of the manufacturing processes and other factors.
14
(4) Pre- and Post-processing
When recycled materials are to be used in earthworks, such as
subgrade and embankment filling, it is necessary to confirm that the location
in which they are to be used satisfies the “Environmental Quality Standards
for Soil Pollution”. If this is done and heavy metals are detected later, it
becomes possible to confirm whether or not they are derived from the recycled
material. It is also necessary for the site manager to record and keep all
documentation on the recycled materials used at the site, in consideration of
the possibility of reuse of the recycled in the future.
(5) Measures for Dealing with Revisions to Applied Standards
All revisions to the JIS and other regulations correspondingly applied
within this manual and enacted after the manual has been published are to
take precedence and be implemented accordingly.
15
3. Manual Configuration
3.1 Contents of the Manual
This manual has been compiled under the prerequisite that the
quality and environmental safety of all materials included here must be
guaranteed when they contain materials recycled from other industries.
Problems with the physical properties and durability of materials are solved
mostly by mixing and processing them with other materials, or by seeking out
methods of use that match up with the characteristics of the recycled
materials. However, there are materials that are difficult to detoxify in order
to ensure environmental safety, and that is why this manual has been divided
into several chapters and the contents separated in the following manner.
Chapter Two: Describes uses for recycled materials that have relatively high
levels of reliability.
This chapter is entitled “Technology Utilization Manual” and provides
information on the recycled materials that are suitable for general use, as
well as their usage methods.
Chapter Three. Describes those recycled materials for which few
investigations have been done or results accumulated, but which are thought
to be suitable for test use.
This chapter is entitled the “Test Installation Manual” and provides
information on the recycled materials that are suitable for use if they are
tested beforehand, and their methods of use.
Chapter Four: Describes the materials for which almost no reports on results,
etc., have been made and for which, therefore, it is impossible to determine
technological standards at the present time.
This chapter is entitled “Materials Requiring Future Investigation” and
simply provides technical information on recycled materials that require
future investigation.
If, as a result of the tests, a method of use of a material listed in the “Test
Facility Manual” is verified, then the material will become one that is suitable
for general use thereafter as long as it is used for the purposes described by
the test method.
16
3.2 Annotation Conventions
Chapter Two basically follows the format shown below and contains the
main text and explanations.
Chapter One. The chapters indicate the types of raw materials.
１．○○○○○
1.1 ○○○○○ Article One, Chapter One. The articles indicate the methods of
processing recycled materials.
1.1.1 ○○○○○
Clause One, Article One, Chapter One. The clauses indicate
the uses and scopes of application of the recycled
materials.
(1) Range of Application
(2) Test Evaluation Methods
1) Quality Standards and Test Methods
2) Environmental Safety Standards and Test Methods
(3) Technology Utilization
1) Design Methods
2) Installation Methods
3) Records
(4) Problems to be discussed
Chapter Three has the same format as that of Chapter Two. To maintain a
more liberal style, though, there is no clear distinction between the main text
and the explanations.
Information on the current condition and application of recycled materials
has been listed in Chapter Four without sticking to any specific format.
4. Terminology Definitions and Explanations
(1) Chapter One. Common Elements
– Waste Material
Unwanted solid or liquid articles stipulated in the “Waste Disposal and
Public Cleansing Law” (Law No. 137, enacted on December 25 1970) that have
been used by the owners or cannot be sold for monetary return to other people.
Divided into two classifications; “Industrial Waste” and “General Waste”.
– Industrial Waste
Waste generated through commercial activities that are stipulated by the
law (Waste Disposal and Public Cleansing Law, Law No. 137, enacted on
17
December 25 1970) and other ordinance. Items that are not covered by this
classification are handled as general waste. Of the industrial waste, waste
that requires handling in accordance with special standards (such as
explosives, poisons, or infectious and other waste that can affect human
health or the environment) is classified as Industrial Waste Subject to
Special Control and General Waste Subject to Special Control.
– Recycled Materials
Reusable resources that have been manufactured at recycling facilities and
are suitable for reuse.
– Law on Promoting Green Purchasing
One of the laws included in the Fundamental Law for Establishing a
Sound Material-Cycle Society. Enacted in May 2000 from the viewpoint that
in addition to working from the supply of recycled goods, it is also important
to increase demand for the purpose of establishing a recycling society.
This law stipulates that, in addition to government and other public offices
taking the initiative to procure environmentally-friendly products and
services (products and services that reduce the burden on the environment),
they must promote the creation of a sustainably developing society by
facilitating the provision of applicable information related to
environmentally-friendly products and services and consequently achieving
transformation of the market.
– Recycled Resources
Collected waste products or by-products that have been used once or not
used at all, and are usable and can be used as raw materials or recycled.
– New Materials
Raw materials used as new materials; excludes recycled materials.
– By-products
Products obtained secondarily from public works construction projects,
product manufacturers, and other sources.
– Recycled Materials Generated by the Construction Industry
Recycled materials of which raw materials are usable as resources
generated from construction projects.
– Recycled Materials Generated by Other Industries
Recycled materials of which raw materials are usable as resources
18
generated by industries other than the construction industry.
– Repeated Reuse Capability
The ability of recycled materials that have been generated by other
industries, used in public works projects, and then regenerated as
construction by-products to be reused repeatedly as recycled materials
generated by the construction industry.
– Environmental Safety
Conditions under which the effects of development on the soil and
ecosystem do not hinder the protection of human health and protection of the
environment.
– Environmental Quality Standards for Soil Pollution
Standards that stipulate the conditions (effluent standards) for 25
substances (currently 27 substances, with the addition of fluorine and boron
in 2001) in soil effluent tests. These conditions are considered desirable to
maintain human health and to protect the environment and are based on the
environmental conditions relating to soil pollution laid down in Clause 1,
Article 16 of the Basic Environment Law (Law No. 91, enacted on Nov. 19
1993).
– Soil Contamination Countermeasures Law
Law that stipulates measures to deal with soil contamination, such as
analyzing the condition of the contaminated soil and preventing health
hazards from soil contamination. The law was enacted in light of growing
concern about the human health effects of soil contamination by toxic
substances and social demands for the establishment of measures against
contamination. The law was enacted on May 22 2002 and released by the
Ministry of Environment on May 29 2002.
– Enforcement Regulations of the Soil Contamination Countermeasures
Law
Ministry of the Environment Ordinance No. 18, made public on December
26 2002. In Clauses 1 and 2, Article 18, the ordinance lists the maximum
toxic effluent limits (effluent standards) for 26 special toxic substances that
can be included in soil, and in Clauses 2 and 3, Article 18, it lists the
maximum toxic content limits (content standards) of nine special toxic
19
substances that can be included in soil.
– Effluent Tests
Tests that evaluate the toxic substances included in solid matter in purified
water or under other predetermined conditions to measure the volume.
(2) Chapter Two, Technology Utilization Manual; Chapter Three, Test Facility
Manual; Chapter Four; Appendix
1) Incineration Ash, Sewage Sludge
– Sewage Sludge Incineration Ash
The ash that is left after the dehydration and incineration of sewage sludge.
This includes coal ash-type incineration ash and high molecular-compound
incineration ash. The former is the ash to which calcium hydroxide, iron
chloride, or other coagulants are added during the dehydration process, which
is the process before actual incineration. The latter is the ash to which high
molecular-compound coagulants have been added prior to dehydration.
– General Incineration Ash
Incineration ash from general waste; emitted from furnaces at waste
disposal plants.
2) Waste Wood, Waste Glass, Used Paper
– Clinker Ash
Coal ash collected from the bottoms of fine-ash incineration boiler furnaces.
It is fragmented into grit and stored after being dehydrated in dehydration
tanks and the like.
– Fly Ash
Fine coal ash collected from the combustion gas in fine-ash incinerator
boilers by dust collectors.
– Waste Wood
Wood or waste wood that is generated and disposed of by construction
projects, land clearing, woodcutting, manufacturers of wooden products,
manufacturers of pulp, and wholesaling of imported wood and the like.
– Thinned Wood
Small-diameter wood collected in forestry thinning operations. Thick
timbers with overall diameters of between 14 and 16 cm are used as materials
20
for posts and beams, but wood with a smaller diameter than the above is
disposed of in forests. The waste materials covered in this manual are deemed
to be waste wood.
– Glass Cullet
Glass such as bottles, etc., that is finely fragmented for particle size
classification.
– Used Paper
Paper that has been used or shipped by paper manufacture and then
collected for the purpose of recycling. Unused but unwanted paper collected
from printing factories, binderies, or the like is also included in this category.
– Bark Compost
Compost in which poultry manure, urine, or other sources of nitrogen are
added to tree bark and allowed to ferment. Approximately 50 kg of poultry
manure and between 10 and 20 kg of ammonium sulfate or urine are mixed
into each ton of tree bark (40% to 50% moisture), and the moisture content is
raised to between 50% and 60% to generate compost.
– Mulch
Made out of tree bark, straw, vinyl sheeting, and other materials and covers
the surface of the soil for the purpose of retaining heat and preventing drying,
weed growth, and corrosion, etc.
– Returnable Bottles
Sake (1.8-L) bottles, beer bottles, milk bottles, and other glass bottles that
can be used repeatedly. Known as “live” bottles.
– One-way Bottles
Glass bottles that are disposed of after a single use.
3) Melting and Solidification, Sintering
– Molten Slag
Non-metallic substances obtained when recycled resources are melted in
melting furnaces and the molten liquid is cooled. Depending on the method of
cooling, the types of slag are categorized as water-granulated slag and
air-cooled slag, etc.
21
– Water-granulated Slag
Finely powdered slag with vitreous characteristics; obtained when the
molten liquid is rapidly cooled by water.
– Air-cooled Slag
The slag obtained when the molten liquid is cooled by air. Slowly-cooled
slag has crystallization levels that are increased by controlling the
temperature during the cooling period.
– Glass Slag
Supercooled liquid is obtained when no abordnary volume changes occur,
even when the point of coagulation is reached during the rapid cooling of
molten liquid. If this supercooled liquid is cooled to a certain temperature
(glass-transition point), it solidifies without crystallizing and becomes solid
glass slag.
– Crystallized Slag
When the molten liquid is cooled slowly, it solidifies at the melting point to
become solid crystals. In ideal crystallized form, the molecules are lined up in
an orderly fashion. Crystallized slag is obtained by slowly cooling the molten
liquid through temperature control.
– Residual Ash
Ash that remains beneath the grates in stoker-type incinerators.
– Sintering
Phenomenon in which powder fuses together and become solid with a
certain amount of strength when it is heated to a temperature below the
melting point or to a temperature at which partial melting occurs.
– Calcination
Sintering of materials that have been shaped. In this manual, “calcinated”
refers to substances that consist of raw materials created from sintered
products (primary products) to which additives have been mixed to form the
shape and then sintered in furnaces.
– Fly Ash
The fine ash that moves with the exhaust gas when waste materials are
incinerated and is then collected by dust collectors, etc.
22
– Sintered Crushed Cement
Cement that consists mainly of incinerated city waste ash, sewage sludge,
and the like. Incineration ash, sewage sludge, and other general city wastes
and mixtures of materials whose quality is governed by the use of natural
materials such as limestone are incinerated in rotary kilns or the like at 1,300
degrees Celsius or higher. Calcium sulfate is added to the semi-molten object
(clinker) obtained and then cooled down to be crushed.
– Incinerator Residue Melting Method
Method of melting inorganic residue (incineration ash, fly ash) under
high-temperature conditions that generally exceed 1,200 degrees Celsius.
These conditions are generally created during the waste incineration process
with the thermal energy obtained from the combustion of fuel and electricity.
– Gasification Melting Method
A melting method that thermally decomposes the waste and burns the gas
generated by the deposition while melting the ash, non-combustibles and the
like. There are two methods available: one that performs thermal
decomposition and melting simultaneously, and one that performs them
separately.
4) Roads
– Manual for Design and Construction of Asphalt Pavement, Manual for
Design and Construction of Concrete Pavement, and Summary of Simple
Paving
Old policies related to paving. These policies are now covered by the newly-issued
“Technical Standards and Descriptions of Pavement Structures”, the “Guidelines for
Pavement Design and Construction”, and the “Guidelines for Pavement Construction”,
but as there are certain points that are not included in the new standards, these policies
will be used in combination for the time being.
– Technical Standards and Descriptions of Pavement Structures
Stipulates the ministerial ordinance related to the standards for pavement
structures, in accordance with revisions to the Road Construction Ordinance
for the purposes of adopting pavement that reduces the burden on the
environment and regulating the properties of pavement structures. The
23
paving-structure technical standards that specify the contents of this
ministerial ordinance were announced by the Ministry of Land,
Infrastructure, and Transportation, and the Japan Road Association
compiled them into an explanatory book.
– Guidelines for Pavement Design and Construction
This book was issued by the Pavement Committee of the Japan Road
Association as a series of practical guidelines to support understanding of the
decisions made by engineers in the field of pavement. The aim is to
appropriately and efficiently implement the details stipulated in the
newly-enacted Technical Standards for Pavements.
– Manual for Pavement Construction
Reference literature and documentation based on the conventional Manual
for Design and Construction of Asphalt Pavement, Manual for Design and
Construction of Concrete Pavement, and Summary of Simple Paving.
Compiled by the Japan Road Association as a technical manual for carrying
out appropriate paving construction work.
– Interlocking Blocks
Interlocking concrete blocks manufactured by the high
vibration-pressurizing instant method for use as pavement. When installed on
roads, these blocks are laid on a bed of cushioning sand, and more sand is then
poured between the joints. The interlocking feature functions to disperse the
load, and although the sides are usually formed in waves in order to achieve
the effects of interlocking, there are also straight blocks available that do not
have wave patterns on the sides.
– Modifying Material
Material added to asphalt mixture used for paving roads with heavy traffic
to prevent the formation of deep furrows on the surface of the asphalt. Types
of modifying material include rubber and thermoplastic elastomer, and the
asphalt to which these materials are added is known as modified asphalt.
– Sub-base Course
Lower layer of subgrade of a paved road when two or more layers are used.
– Base Course
Upper layer of subgrade of a paved road when two or more layers are used.
The base course lies beneath either the surface or foundation layers of the
24
asphalt pavement or the concrete pavement plates; the stress applied is larger
than that applied to the sub-base course.
– Compaction Rate
The level at which the material used in various foundation and surface
layers on a road-bed and in subgrade layers is to be compacted (tamped) upon
construction. This is usually expressed in percentages of a standard density.
– Revised CBR
Index expressing the strength of a granular material, such as crushed
stone, grit, or sand, that is used as subgrade. Obtained by separating the
subgrade into three layers in accordance with the methods stipulated in JIS A
1211 and tamping each layer 92 times. The compaction rate in localized areas
for maximum dry density is expressed with the corresponding CBR. The
compaction rate is measured when tamping has been performed 92 times for
each level at a dry density of 95%.
– Equivalent Conversion Factor
The value that shows the equivalent strength-wise thicknesses of the
surface and foundation layers of a hot asphalt mixture. The layers are
considered 1 cm thick for each material and the construction method used for
each layer is that used for asphalt pavement.
5) Concrete and Ground Slabs
– Epoxy Resin-coated Reinforcing Steel
Reinforcing steel to which an epoxy resin coating has been added by
electrostatic powder coating.
6) Miscellaneous
– Surface Dry Density
The value obtained by dividing the weight of the surface dry-saturated
aggregate by its absolute volume.
– Water Absorption Rate
The ratio of the weight of the water contained in water-saturated aggregate
and the weight of the solid portion in th aggregate. Usually expressed as a
25
percentage.
– Recycled Rubber
Vulcanized rubber that has been processed physically or chemically to give
it adhesiveness and plasticity so it can be used for the same purposes as raw
rubber or non-vulcanized rubber.
(Reference Material)
1) City Bureau, Ministry of Construction: Guidelines for the Use of Sewage
Sludge for Urban Greening Projects, September 1995
26
Chapter Two. Technology Utilization Manual
27
1. General & Industrial Waste Incineration Ash
Overview of Waste
According to an environmental white paper published in 2004, the amount of
general waste generated in fiscal year 2001 was 1,124 g/day per citizen, and the annual
total for the entire nation came to 52.1 million tons (enough to fill the Tokyo Dome
baseball stadium 140 times); 78.2% was treated by direct incineration. The amount of
incineration ash (incineration ash from city waste) generated on a yearly basis is
approximately 7.2 million tons (based on fiscal year 2001 figures,) and the vast majority
of this is still being buried in landfills.
(1) Process Overview
Incineration is carried out on general waste as an intermediate process, and the
incineration residue (ash), which has between 1/20th and 1/30th the volume of the
material prior to incineration, is landfill-processed at final processing plants. However,
the remaining capacity of the final processing plants is gradually decreasing, and
difficulties are being experienced in acquiring land for new final processing plants owing
to fears over the pollution of the surrounding environment.
The solubilization and solidification process is a process in which waste is melted
under conditions of at least 1,200 degrees Celsius and then either water-cooled or
air-cooled to solidify it. The use of high temperatures reduces the amount of final product
by dissipating and melting down the volatile substances; it also unifies the overall quality
of the remaining substances and removes all the toxins. It is an effective method of
processing because the solid matter left over can be efficiently used. This process reduces
the incineration residue (ash) of the entire content by approximately half. Although the
solubilization and solidification process leaves slag and slight traces of metal in the end
product, the majority of this slag consists mainly of SiO２, CaO, and Al２O３.
The cooling process separates the slag into water-granulated slag and air-cooled
slag. Water-granulated slag is produced by rapidly cooling by bringing the melt into direct
contact with water. The main feature of this is that the end product has the consistency of
glass and resembles fine sand. Air-cooled slag is slag generated by cooling the melt in air
for the purpose of forming slag blocks and by extending the cooling period so that the slag
can be crystallized. A slag block that has been cooled slowly and allowed to crystallize is
28
known as slowly-cooled slag, but this is included in the category of air-cooled slag.
Allowing plenty of time for cooling and maintaining an appropriate degree of basicity in
the production process for air-cooled slag creates a crystallized slag that resembles basalt
or some other type of igneous rock as the crystallization process advances. The
solubilization methods are categorized in Fig. 1.1-1.
The solubilization and solidification process can be divided into two major
processes: the process in which waste is incinerated into ash and the incineration residue
is melted, and the process in which the waste is melted directly without prior treatment.
The former method, in which the incineration residue is melted, is also divided into two
methods: the fuel combustion method, in which oil, coke, or other fuel is burned to melt
the residue with the generated heat, and the electrical method, in which the residue is
melted with the thermal energy generated by electricity. The latter is known as the
gasification melting method, by which the organic matter within the waste gasifies under
oxygen-free conditions and consequently the inorganic matter is melted at high
temperatures. The gasification melting method can be carried out in a single furnace, or
the process can be carried out using different furnaces. The amount of carbon dioxide
emitted by the fuel from one ton of general waste when it is incinerated is 0.005 tons, and
0.05 tons of incineration waste is generated. Consequently, 0.1 ton of carbon dioxide is
generated for each ton of incinerated ash.
As approximately 200 liters of heavy oil is required to melt one ton of
incineration ash, and the amount of carbon dioxide emitted from the fuel during the
melting process is 0.52 tons. As a result of this, 0.65 tons of slag is produced.
Consequently, in order to produce one ton of molten slag, 0.95 tons of carbon dioxide is
generated when this is added to the incineration process of the general waste.
29
(2) Physiochemical Properties
1) Properties and Composition of Incineration Ash
The composition of incineration ash is an important factor that affects the
properties of the slag. A table of the compositions of incineration ash examples, quoted
from a report issued by the City of Tokyo, is provided in Table 1.1-1.
Table 1.1-1. Examples of Main Ash and Fly Ash Compositions
Item
Property
Minute
Property
Main Ash
SiO２ (％)
Fly Ash
Water-Cooled
Air-Cooled
Water-Cooled
Air-Cooled
36.1– 57.2
35–49.4
30.5–35.4
19–48.4
Al２O３ (％) 15.3 – 26.6
16.2–26.8
18.3–18.7
7.3–18.4
CaO (％)
13.1–22
27.1–37.5
27.7–41.8
Fe２O３ (％) 0.71–10.2
<0.01–13
0.37–5.41
0.61–10.4
MgO (％)
1.3–5.22
3.07–4.5
4.37–5.5
1.99–5.5
Na２O (％)
2.66–7.8
2.9–7.13
0.38–3.74
0.27–3.3
K２O (％)
0.57–1.7
0.48–2.8
0.12–1.7
0.14–1.5
Cu (％)
0.02–0.09
<0.01–1.4
0.02–0.16
<0.01–0.03
Pb (％)
<0.01–0.06
0.0042–0.022
0.0008–0.04
0.0005–0.03
Zn (％)
0.01–0.67
<0.01–0.15
0.04–0.15
0.01–0.55
Cl (％)
0.03–1.1
<0.1–0.4
0.002–0.64
0.15–8.6
Cd (mg/kg)
10.4–32.49
<0.005–5
<5
<0.4
<0.001–5.51
As (mg/kg)
<0.5–10
<0.05–3.4
<0.5
<0.001–1.45
Hg (mg/kg)
<0.005–0.5
<0.01–0.072
<0.01
<0.01–0.43
Source: Report of Surveys into Processing Technology for Specially-Controlled Waste, City of Tokyo
The main components of main ash (the ash that collects at the bottom of
furnaces) are silicon dioxide (SiO２), calcium oxide (CaO), and aluminum oxide (Al２O３),
which are also found in glass. The main components of fly ash (the ash collected in dust
collectors) are calcium oxide (CaO) and silicon dioxide (SiO２). It is assumed that because
calcined lime and slaked lime are used in toxic gas removal equipment and the like,
which are used in the melting process, fly ash contains more calcium oxide than does
main ash. Also, the high percentage of chloride (C1) is thought to be a result of the
chloride vaporizing at high temperatures and adhering to the ash.
2) Physiochemical Properties
Examples of the physical properties of water-granulated slag and air-cooled
slag are shown in Table 1.1-2.
30
The surface dry density of water-granulated slag is approximately 2.7 (g/cm3),
which is slightly heavier than the general 2.5 to 2.6 (g/cm3) values for natural sand. The
average moisture absorption rate is 1.0%, indicating a lower density than the 1.5% to
2.5% obtained with natural sand. The average percentage wear value is 37%, which
satisfies the quality target of less than 50% for crushed stone used in the upper stratum
of subgrades, as stipulated by the Guidelines for Pavement Design and Construction.
The revised CBR value is 19%, which alone does not satisfy the quality standard of 20%
or more for crusher-run, as stipulated by the Guidelines for Pavement Design and
Construction.
There are very few data available on air-cooled slag. When this is analyzed
together with slowly-cooled slag, the surface dry density is 2.8 (g/cm3), which is slightly
heavier than the general 2.5 to 2.6 (g/cm3) values for natural sand. The average
moisture absorption rate is 1.1%, which indicates a lower density than the 1.5% to 2.5%
values obtained with natural sand. The average percentage wear value is 26%, which
satisfies the quality target of less than 50%. The revised CBR value is 54%, which is
more than sufficient to satisfy the quality standard of 20% or more for crusher-run.
Table 1.1-2. Physical Properties of Water-granulated slag and Air-Cooled Slag
Water-granulated
Item
slag
Average
Apparent Density (g/cm3)
Surface Dry Density
Air-Cooled Slag
Average
2.74
(g/cm3)
2.73
2.8
Absolute Dry Density (g/cm3)
2.70
2.8
Unit weight (kg/l)
1.51
1.7
Moisture-absorption Rate (%)
1.03
1.1
Solid Content (%)
60.5
54.8
Stability (%)
5.08
0.6
Wash Test (%)
1.3
0.2
37.3
25.7
1.71
2.4
9.2
2.5
19.3
53.8
Los Angeles Abrasion Test (%)
Maximum Dry Density
(g/cm3)
Optimum Moisture Content (%)
Revised CBR (%)
31
An example of particle distribution in water-granulated slag is shown in Fig.
1.1-2.
Water-granulated slag is coarser than fine aggregate, and there are very few fine
particles with diameters of 0.6 mm or less.
100
Passing Mass Percentage (%)
90
80
70
60
Coke-bed ash melting furnace
Plasma melting furnace
Surface melting furnace
Arc melting furnace
Fine aggregate upper limit
Fine aggregate lower limit
50
40
30
20
10
0
0.15
0.30
0.60
1.2
2.36
4.75
10
31.5
Particle Size (mm)
Fig.1.1-2. Example of Particle Distribution of Water-granulated Slag
Examples of the physiochemical properties of water-granulated slag and
air-cooled slag are shown in Table 1.1-3. The main components of the slag are SiO２, CaO,
and Al２O３, the total of which account for approximately 80% of the slag, and the
percentage composition depends on the properties of both the material that is targeted
for processing and all the additives (materials used to adjust basicity). The tendency for
the composition to fluctuate in accordance with the cooling method is not recognized.
Table 1.1-3. Examples of the Physiochemical Properties of Hydro-pulp
Slag and Air-Cooled Slag
32
Overall
Average
SiO２ (%)
37.3
Hydro-pulp
Maximum
53.7
Air-cooled
Minimum
23.0
Maximum
50.0
Minimum
16.3
CaO (%)
24.6
45.0
16.5
28.9
13.1
Al２O３ (%)
17.2
21.2
14.9
24.7
8.8
Fe２O３ (%)
6.1
16.7
1.6
13.0
3.1
TiO２ (%)
1.2
1.5
0.8
1.6
1.0
MgO (%)
2.6
3.5
1.7
5.0
2.0
Na２O (%)
3.5
4.5
0.6
7.0
0.6
K２O (%)
0.9
1.5
0.2
0.5
0.1
Examples of measurements of the heavy metal content in water-granulated slag
are shown in Table 1.1-4.
The amount of heavy metal contained in slag depends on the contents of the
materials to be processed and the shape and processing conditions (temperature,
atmosphere, etc.) of the melting furnace, and the range of fluctuation is great.
Table 1.1-4. Examples of Measurements of Heavy Metal Content in Water-Granulated
Slag
Maximum
Hg (mg/kg)
0.0707
Minimum
< 0.001
Maximum
As (mg/kg)
100
Minimum
0.402
Cd (mg/kg)
0.53
< 0.5
B (mg/kg)
1,800
29.9
Pb (mg/kg)
440
7.8
Mo (mg/kg)
86
< 1
Cu (mg/kg)
2,300
26.8
Ni (mg/kg)
110
< 10
Zn (mg/kg)
5,870
15.4
Sb (mg/kg)
100
< 0.5
Cr (mg/kg)
1,300
1.7
Se (mg/kg)
38
< 0.1
Technical Report A 0017:2002, “Subgrade Road Aggregates using Solubilized
and Solidified General Waste and Sewage Sludge”, was published by the Ministry of
Economy, Trade, and Industry in July 2002. The report regulates the quality, testing
methods, inspection, display, and reporting methods for general waste and sewage sludge
molten slag used as aggregate for hot asphalt mixture and subgrade materials. However,
33
as these materials were not covered under the Japanese Industrial Standards as of
March 2005, solubilization and solidification processing facilities do not always
manufacture and ship molten slag on the basis of these quality regulations. It is therefore
necessary to implement inspections to confirm the quality of each product when molten
slag is used as road aggregate and the like.
[Reference]
1) Japan Waste Research Foundation: Manual for the Effective Use of Slag (Guidelines
for the Reuse of General Waste Solubilization and Solidification Materials), 1999
2) Japan Society of Industrial Machinery Manufacturers, Eco-Slag Recycling Promotion
Center: Fiscal Year 2001 Report on Research into Reducing and Circulating Sludge and
Incineration Ash, July 2002
(3) Eco-Slag Recycling Promotion Center, Japan Society of Industrial Machinery
Manufacturers: Points for Consideration and Data Collection on the Effective Reuse of
Garbage and Sewage Slag (Eco-Slag) for the Creation of a Circulatory Society, June 2002
4) Ministry of Economy, Trade, and Industry: Technical Report (TR A 0017:2002) Road
Aggregates using Solubilized and Solidified General Waste and Sewage Sludge, July
2002
34
1.1.1 Paving Road-Bed Materials
This section applies to the design and construction of road pavementing and subgrade
material using molten slag generated from general waste and incineration ash.
[Description]
The molten slag used as a road-bed material consists of general waste or
incineration ash that has been melted at temperatures of 1,200 degrees Celsius or higher,
and it must conform to the safety standards to be described later.
The molten slag is used as a subgrade material. Arenaceous water-granulated
slag is used on its own as a sub-base course, and is used as both a base and sub-base
courses when combined with crusher-run or other materials. Slowly-cooled slag block is
used on its own or in combination with other recycled subgrade materials as base and
sub-base courses.
The design traffic volume classification for pavement made using molten slag is
T<1000 (vehicle/day/direction) for both water-granulated slag and slowly-cooled slag. It is
therefore necessary to decide whether or not the molten slag may be used for subgrade
stabilization or for roads with design traffic volume of T 1000 (vehicle/day/direction), in
accordance with the operation results and test results for the slag.
35
1) Quality Standards and Testing Methods
The physical aspects of the subgrade material made using molten slag must satisfy the
quality standards for crusher-run and size-controlled crushed stone stipulated in the
Guidelines for Pavement Design and Construction.
The tests on quality stipulated by the quality standards are performed in accordance
with the instructions laid out in the Guidelines for Pavement Test Methods.
(1) Safety Standards
The effluents of toxic materials must satisfy the effluent standards stipulated in “On
Promotion of the Reuse of Solidified Molten General Waste (Ministerial Announcement
No. 508, March 26 1998, Environmental Health Division, Health Service Bureau, Ministry
of Health, Labor, and Welfare) (hereinafter referred to as the Molten Slag Standards).
The toxic content of materials must satisfy the content standards stipulated for the
above-mentioned six substances in Clauses 2 and 3, Article 18 of the “Enforcement
Regulations of the Soil Contamination Countermeasures Law” (Ministry Ordinance No.
29, December 26 2002, Ministry of Environment) (hereinafter referred to as the Toxic
Content Standards).
(2) Test Methods
Effluent tests are to be carried out in accordance with the stipulations laid down in the
“Environmental Quality Standards for Soil Pollution” (Ministry of Environment
Ministerial Announcement No. 46, August 23 1991).
Toxic content tests are to be carried out in accordance with the stipulations laid down in
the “Measurement Methods Concerning Surveys of Toxic Content in Soil” (Ministry of
Environment Ministerial Announcement No. 19, March 6 2003).
(3) Safety Management
The orderer of the slag must implement effluent tests on each lot of molten slag and use
slag for which a quality rating based on the test results is shown.
[Description]
Re: 1) When molten slag aggregate is used as road-bed material, the aggregate
used must conform to the regulations on molten slag aggregates for roads, as stipulated in
the technical report (TR A 0017) that publicizes the molten slag aggregate for use in roads.
The types and names of slag for use as subgrade are stipulated in TR A 0017, as shown in
36
Table 1.1.1-1.
Table 1.1.1-1. Types and Names of Slag for Use as Road-Bed
Type
Name
Application
Size-Controlled Solubilized
MM‒40
Base Course
and Solidified Aggregates
MM‒30
(Slowly-cooled Solids))
MM‒25
Crusher-Run Solubilized and
CM‒40
Solidified Aggregates
CM‒30
(Slowly-cooled Solids)
CM‒20
Sub-base Course
The levels of granulation for molten slag aggregates for roads are stipulated as
shown in Table 1.1.1-2, and the physical quality levels are stipulated as shown in Table
1.1.1-3.
Table 1.1.1-2. Level of Granulation for Molten Slag Aggregates for Roads
Name
MM-40
Parti
Percentage (%) of Material that Passes Through a Metal Sieve
cle
Nominal Size of Sieve Holes (mm)
Range
53
37.5
40‒0
10
95‒100
31.5
26.5
19
13.2
60‒90
0
MM-30
30‒0
4.75
2.36
0.425
0.075
35‒
20‒50
10‒30
2‒10
20‒50
10‒30
2‒10
20‒50
10‒30
2‒10
65
100
95‒100
60‒90
30‒6
5
MM-25
25‒0
100
95‒100
55‒85
30‒6
5
CM-40
40‒0
10
95‒100
50‒80
15‒
0
CM-30
30‒0
5‒25
40
100
95‒100
55‒85
15‒4
5‒30
5
CM-20
20‒0
100
95‒
60‒90
100
20‒
10‒35
50
Table 1.1.1-3. Types and Quality of Molten Slag for use as Subgrade Material in Roads
Test Method
Type
37
Uni Volume
Abrasion Loss
JIS A 1104
JIS A 1121
Size-controlled Solubilized and
Solidified Aggregates (Slowly-cooled
Solids), Crusher-Run Solubilized and
1.5 kg/l
50% or less
Solidified Aggregates
In addition to the above, when molten slag aggregates are used as road-bed
materials they must satisfy the regulations stipulated for paving road-beds, such as the
revised CBR and the like. These materials and an outline of the quality standards for
construction methods are shown in Tables 1.1.1-4 and 1.1.1-5. In this case, the crushed
stone may be considered as crushed stone prepared by mixing with molten slag for
roads.
Although physical features such as particle size or unit volume do not satisfy
TR A 0017, if molten slag aggregate satisfies those qualities when mixed with other
subgrade materials then the slag may be used as mixture. The test methods must
conform to the stipulations laid down in the Guidelines for Pavement Test Methods.
The quality standards for subgrade material using molten slag must conform to
the crusher-run and size-controlled crushed stone quality standards stipulated in the
Guidelines for Pavement Design and Construction. If materials that do not satisfy these
quality standards are stability-treated and used, they will conform to the relevant
quality regulations for road-bed material depending on the type of road pavement, on
whether they are used in sub-base courses or base courses, and on the method of
construction and materials, such as particulate subgrade and stability-treated subgrade,
etc.
The quality regulations for recycled subgrade materials that have been
adjusted to meet the relevant quality standards by mixing recycled asphalt concrete
aggregate with molten slag are stipulated in the Handbook for Reusing Pavement 4).
An outline of these quality regulations is provided in Tables 1.1.1-4 and 1.1.1-5.
Table 1.1.1-4. Quality Regulations for Substratum Road-bed Materials
Construction Method /
Revised CBR % Uniaxial Compression
Materials
Particulate Subgrade
Material, Crusher-run,
PI
２
Strength MPa (kgf/cm )
20 or above
−
#1))
6 or less
#2)
etc.
38
−
Cement Stabilization
Treatment
−
(10)
−
Lime Stabilization
Treatment
Material age: 7 days, 1.0
#3)
Material age: 10 days, 0.7
#3)
(7)
−
#4)
#1) 10 or above for simple paving; #2) 9 or less for simple paving; #3) None for simple
paving.
#4) 0.5 (5) for cement concrete paving. The prescribed particle size is required with
crusher-run. Also, it is desirable for aggregate that is used in stabilization treatment to
have a revised CBR of 10% or more and a PI (Plasticity Index) of 9 or less for cement,
and between 6 and 18 for lime.
Table 1.1.1-5. Quality Regulations for Base Course Materials
Construction
Revised
Uniaxial
Marshall
Other Quality
Method / Materials
CBR %
Compression
Stability kN
Factors
Strength MPa (kgf)
Size-controlled
80 or above #1)
(kgf/cm２)
−
−
PI 4 or less
−
−
3.43 (350)
Flow value: 10
or above
to 40
Crushed Stone
Hot Asphalt
Stabilization
Treatment
Porosity 3% to
Cement
12%
−
−
Material age: 7 −
Stabilization
days #2)
Treatment
2.9 (30)
Lime Stabilization
−
Treatment
Material age:
−
−
10 days #3)
1.0 (10)
#1) 60 or above for simple paving; #2) 2.5 (24) for simple paving; 2.0 (2) for cement
paving.
#3) 0.7 (7) for simple paving.
The percentage of abrasion for aggregates used as base course must be 50% or
less. The prescribed particle size is required for size-controlled crushed stone. Also, it is
desirable for aggregate used in stabilization treatment to have a revised CBR of 20% or
39
more (excluding asphalt,) a PI of 9 or less (between 6 and 18 for coal ash), and a
maximum particle diameter of 40 mm or less.
It is desirable for the basic aspects of molten slag used in road-bed materials,
such as density, moisture absorption, particle size, and external appearance, to be
stable. Therefore, when molten slag used as subgrade material contains a large amount
of iron, this leads to rust and fluctuation of compaction density, so it is desirable that an
appropriate extent of magnetic separation be carried out beforehand. When working
with water-granulated slag that contains acicular (needle-like) matter and
slowly-cooled slag that is vitreous and has many sharp edges, to ensure safety during
transportation and construction, suppress the development of oblate shapes and
occurrence of cracks, and improve the ease of handling of the slag, it is recommended
that the acicular matters be removed and rounding be carried out using an appropriate
crusher or the like.
Picture 1.1.1-1. Water-granulated slag
Picture 1.1.1-2. Glass slag containing
containing acicular matter
sharp edges
There are products for which the surface of the slag has been polished or the slag
has been processed to give it round edges by re-crystallizing it in a rotary kiln in order to
improve the shape of the particles. Photographs of examples of these slags are shown in
Pictures 1.1.1-3 and 1.1.1-4.
40
Picture 1.1.1-3. Example of re-crystallized Picture 1.1.1-4. Example of polished
Slag
slag
The quality tests stipulated in the quality standards are carried out in
accordance with the methods laid down in the Guidelines for Pavement Test Methods.
The basic density and water-absorption tests of materials and molten slag are also to be
carried out in accordance with these guidelines.
Table 1.1.1-6. Test Evaluation Methods for Iron and Acicular Matter in Molten Slag
Quality Aspect
Test Evaluation
Test Method, Etc.
Method
Iron
Measurement of the
Carried out with a magnet
amount adhering to a that is magnetized to a
magnet
predetermined level, or by
low-pitch analysis. Maximum
permissible content is 1%.
Acicular matter in
Measurement of
In accordance with the
water-granulated slag
particle shape
Guidelines for Pavement Test
determination result
Methods 2)
rates
Particles containing glass-like
Measurement of
In accordance with the
sharp edges
particle shape
Guidelines for Pavement Test
determination result
Methods 2)
rates
41
Re: 2)
After the product has met the effluent standards for general waste and
incineration ash molten slag, laid down in “On the Promotion of Reuse of Solidified
Molten General Waste” (Ministerial Announcement No. 508, March 26 1998, Ministry of
Health, Labor, and Welfare) (hereinafter referred to as the Molten Slag Standards), the
effluent standards shown in Table 1.1.1-7 will be acquired. Dioxins and PCBs are dissolved
during the high-temperature melting process at 1,200 degrees Celsius or higher, and six
substances— cadmium, lead, hexavalent chromium, arsenic, total mercury, and
selenium—are covered by the effluent standards for molten slag. As part of the regulations
on toxic content, selection of the above-mentioned six substances out of nine substances
stipulated in Clauses 2 and 3 of Article 18 of the Ministry of Environment’s “Enforcement
Regulations of Soil Contamination Countermeasures Law (Ministerial Ordinance No. 29,
Ministry of Environment, Dec. 26, 2002) (hereinafter referred to as the Toxic Content
Standards,) led to the toxic content standards shown in Table 1.1.1-7.
Table 1.1.1-7. Safety Standards for Molten Slag
Substance
Effluent Standard
Toxic Content
Standard
Cadmium
0.01 mg/1 or less
150 mg/kg or less
Lead
0.01 mg/1 or less
150 mg/kg or less
Hexavalent 0.05 mg/1 or less
250 mg/kg or less
chromium
Arsenic
0.01 mg/1 or less
150 mg/kg or less
Total
0.0005 mg/1 or less 15 mg/kg or less
mercury
Selenium
0.01 mg/1 or less
150 mg/kg or less
(2) Test Methods
The effluent testing method follows the measurement methods explained in the
addendum to “Environmental Quality Standards for Soil Pollution” (Ministerial
Announcement No. 46, Ministry of Environment August 23 1991) (see the separate table in
Section 1 of the Appendix of this manual).
42
The toxic content testing is carried out in accordance with the stipulations laid
down in “On Establishing Measurement Methods Concerning Surveys into Toxic Content
in Soil” (Ministerial Announcement No. 19, Ministry of Environment, Mar. 26, 2003) (see
the separate table in Section 3 of the Appendix of this manual). The manufacturer of the
molten slag that is to be reused as subgrade material must implement the effluent tests on
each lot and record and store the results of quality testing in order to guarantee that the
relevant molten slag conforms to the previously-mentioned safety standards. Users confirm
the safety by checking the test results submitted by the manufacturer. The size of the lots is
determined in accordance with JIS Z 9015 “Discreet Values Sample Examination
Procedures”, or through discussions between the parties concerned.
In the event that the size of the lots has not been predetermined, either the amount
produced over a period of three months or a fixed amount assumed to be the average for the
lots is adopted. In this case, the smaller of the two amounts is used.
If molten slag is mixed with other materials for use as a subgrade material, the
effluent tests on the mixture are not performed by the purchaser. Instead, slag whose
safety has been confirmed by its manufacturer through effluent tests of the slag itself is
selected for use.
The purchaser must confirm that the molten slag delivered by the manufacturer
conforms to the quality standards shown in Table 1.1.1-4 by checking the Test Results
Sheet (shown in Table 1.1.1-8), which is supplied at the time of delivery.
Table 1.1.1-8. List of Items to Be Checked for Safety Quality Display
No.
Item Listed
(1)
Name of Material Used
(2)
Manufacturer’s Name
(3)
Production Plant Name
(4)
Date of Manufacture or Delivery
(5)
Lot Number
(6)
Quantity
(7)
Quality Assurance Display (display assuring the
quality of the product, such as cadmium at 0.01 mg/L
or less, lead at 0.01 mg/L or less, and all other
items stipulated in Table 1.1.1-1.)
43
(8)
Miscellaneous (particle size, physical aspects,
effluent test results, etc.)
Safety inspections are carried out by the manufacturer at the time of shipping
and by the purchaser at the time of receipt. A third-party organization or the like must
check to ascertain that the test results satisfy the test evaluation values during the
inspection at the time of receipt. When safety is confirmed by sample testing, the
sampling method used must conform to JIS Z 9015, “Sample Examination Procedures for
Discrete Values”.
(3) Technology Used
1) Design
The design of subgrade using molten slag aggregates must conform to the methods and
procedures stipulated in the “Guidelines for Pavement Design and Construction”, the
“Manual for Design and Construction of Asphalt Pavement”, the “Manual for Design and
Construction of Concrete Pavement”, and other relevant documentation. However, when it
slag is to be used on roads with a road-paving design traffic volume classification of T
1000 (vehicle/day/direction), molten slag that has a record of usage for such a road is to
be used.
2) Construction
The construction of subgrade using molten slag aggregates must conform to the methods
and procedures stipulated in the Guidelines for Pavement Design and Construction.
3) Maintenance of Logs, and Repeated Reuse and Disposal
When involved in the construction of subgrade using molten slag, the purchaser must store
all plan views, cross-sectional diagrams, quality charts, design plans, and all other
drawings and specifications, together with the results of the tests implemented on the
subgrade material using molten slag and the working diagrams, so that information on the
relevant subgrade material can be used when the subgrade is to be recycled and reused or
disposed of.
[Description]
RE: 1) The design of subgrade using molten slag must conform to the methods and
procedures stipulated in the Guidelines for Pavement Design and Construction. However, as
there is no guarantee that molten slag with the prescribed quality levels can be obtained in
the prescribed quantities, before the subgrade is designed it is necessary to investigate some
44
aspects related to the subgrade material, such as the supplier, the quality levels (including the
results of effluent tests), the production capacity, and the transportation distances.
Although an equivalent conversion coefficient corresponding to the quality standard
for subgrade materials made with molten slag is used in the design of subgrades for asphalt
pavement, as mentioned above, the only usage result for the design traffic volume
classification is for particulate subgrade material and size-controlled subgrade material for a
road of T < 1000 (vehicle/day/direction). Therefore, it is necessary to confirm performance
of the material on test paving, etc., when it is to be used on large roads that exceed the T
value of the paving traffic volume.
RE: 2) The construction of subgrades that use molten slag must conform to the
methods and procedures stipulated in the “Handbook for Pavement Construction” or the
like, depending on the methods and procedures of construction５) There are cases in which
the particles on the surfaces of air-cooled slag areas are crushed by metal rollers, exposing
sharp edges. In this event, careful and quick treatment of the base course is needed.
When subgrade materials that use molten slag are handed over to the purchaser,
the purchaser must receive reports on the test results at the same time and confirm the
details of the results of effluent tests and other tests.
RE: 3) When involved in the construction of subgrade using molten slag, the
purchaser must store all plan views, cross-sectional diagrams, quality charts, design plans
and all other drawings and specifications, together with the results of the tests implemented
on the subgrade material using molten slag and the working diagrams, so that information on
the relevant subgrade material can be used when the subgrade is to be recycled and reused or
disposed of. The purchaser must submit the test result reports, construction plans, and other
relevant documentation to the construction contractor, and this documentation must then be
stored. With regard to the repeated use, reuse, and disposal of subgrade materials made from
molten slag, the details listed in the working diagrams and the like at the time of use of the
subgrade material must be verified, and appropriate methods and procedures must be
established through discussions and through agreement between the purchaser and the
manufacturer of the molten slag.
45
(4) Points for Consideration
As the properties of molten slag differ depending on the solubilization and solidification
facility and on the production conditions, it is necessary to investigate the quality of the
molten slag before it is used. It is also necessary to verify whether the material satisfies
the requirements of usage.
2) Usage Results
Although some records exist for the use of molten slag as subgrade material,
environmental safety levels over the extreme long-term are still being verified. In
addition to the results for using molten slag as subgrade material on its own, there are
also results available for the usage of molten slag when it is mixed with other materials.
Therefore, in the event that the quality of the molten slag, in terms of particle size and
other factors, is not good, it is necessary to establish methods of meeting the required
performance levels (for example, by mixing it with natural materials).
3) Supply
As the number of manufacturing plants that produce molten slag is limited, it is
necessary to initiate investigations into productivity and supply routes, etc.
4) Carbon Dioxide Emissions
As molten slag is melted at temperatures of 1,200 degrees Celsius or higher during the
manufacturing stage, the amount of carbon dioxide is emitted is larger than that
emitted when disposing of general waste by the conventional process, which incinerates
materials into ash at approximately 800 degrees Celsius.
[Description]
RE: 1)
As the properties of molten slag, especially with regard to the iron content, particulate
shape, and amount of acicular crystals in water-granulated slag, differ depending on the
solubilization and solidification facility and on the production conditions, it is necessary
to investigate the quality of the molten slag before it is used.
Also, the policies shown in the Guidelines for Pavement Design and Construction are
different from the conventional policies. The conventional policy was based on the
specification code, whereas the present one is based on specific safety guidelines. As the
quality standards of the materials or the like are specification codes, but the road
surface and subgrade follow specific safety guidelines, it is necessary to discuss and
investigate whether the materials and construction methods satisfy the performance
46
requirements without being constrained by the quality standard alone.
RE: 2) According to Reference 6), more than twenty examples of construction results in
which molten slag has been used in subgrade materials are available, and the number is
expected to increase in the future. There are cases in which molten slag has been mixed
with other materials, so it is necessary to initiate investigations into how molten slag is
used by mixing with other ordinary materials and to then implement size control if the
molten slag does not have a suitable particle size.
RE: 3) The number of manufacturing plants that produce molten slag is limited. The
amount produced in these facilities is also comparatively small—between about ten tons
and several dozen tons per facility per day—and the amount stocked tends to be
generally small. On the other hand, most road construction projects require between
several hundred tons and several thousand tons of subgrade material. It is therefore
necessary to investigate productivity and supply routes to obtain the required amount
of molten slag at the required time at a cheaper price when molten slag has been
selected as the subgrade material.
RE: 4) The method of constructing subgrades that use molten slag is the same as the
method that uses new material. Therefore, the same amount of carbon dioxide is
generated during construction.
As molten slag is melted at temperatures of 1,200 degrees Celsius or higher in the
manufacturing process, the amount of carbon dioxide that is emitted is larger than that
emitted when general waste is disposed of by the process previously used, in which the
waste was incinerated into ash at approximately 800 degrees Celsius. However, the new
method has the advantage of improved safety levels with regard to dioxin
countermeasures and effluent.
Other issues to be considered are as follows:
(1) Environmental Safety
As molten slag is melted at temperatures of 1,200 degrees Celsius or higher, there are
few problems with regard to environmental safety.
(2) Repeated Use
When subgrade made from molten slag aggregate that was problem-free during its
usage period is repeatedly used, the molten slag aggregate may be regarded as ordinary
aggregate.
(3) Financial Viability
It is assumed that the cost of producing a ton of molten slag is several tens of thousands
47
of yen, but the market price is not determined by product cost but by supply and
demand. As there is very little difference between construction methods using molten
slag and those using ordinary aggregates, there is probably not much difference in
construction costs.
(4) Necessity
The incineration ash is generated through incineration processing by local municipal
authorities. It is therefore necessary to give considerable thought to the use of
incineration ash for projects commissioned by local municipal authorities.
[Reference Materials]
1) Ministry of Economy, Trade and Industry: Technical Report (TR A 0017:2002)
Subgrade Aggregates that Use Solubilized and Solidified General Waste and Sewage
Sludge, July 2002
2) Japan Road Association: Guidelines for Pavement Test Methods, November 1988
3) Japan Road Association: Guidelines for Pavement Design and Construction, February 2002
4) Japan Road Association: Pavement Reuse Guidelines, February 2004
5) Japan Road Association: Pavement Construction Guidelines, February 2002
6) Eco-Slag Recycling Promotion Center, Japan Society of Industrial Machinery
Manufacturers: Points for Consideration and Data Collection on Effective Use of Molten
Slag Generated from Garbage and Sewage Slag (Eco-Slag) for the Creation of a
Circulatory Society, June 2002
7) Japan Waste Research Foundation: General Report on Slim-Waist Promotion Research,
Pages 101 to 110, March 1995
8) Nishizawa, et al.: Test Paving Using Molten Ash Slag, 14th Japan Road Congress
Thesis Collection, Pages 209 to 210, October 1979
9) Nakamura et al.: Evaluation of the Suitability of Molten Ash Slag as Subgrade
Material for Roads, 9th Japan Society of Waste Management Experts’ Collection of
Presented Theses, Pages 433 to 435, October 1998.
10) Nemoto et al.: Molten Slag as Aggregate, 9th Japan Society of Waste Management
Experts’ Collection of Presented Theses, Pages 436 to 439, October 1998.
11) Hakusegawa et al.: Use of City Waste Incineration Molten Ash Slag as Subgrade
Material, 22nd Japan Road Association Thesis Collection, Pages 660 to 661, October 1997
48
1.1.2. Aggregate Used for Surface and Binder Courses of Asphalt Pavement
This section applies to the design and construction of surface and binder courses of
asphalt pavement that uses molten slag aggregate generated from general waste or
incineration ash.
[Description]
Molten slag aggregate that is used for the surface and binder courses of asphalt
pavement is generated from general waste or incineration ash that has been melted at
temperatures of 1,200 degrees Celsius or higher and then cooled for solidification, and it
must conform to the safety standards to be described later.
There are two types of molten slag: slowly-cooled slab slag and arenaceous
water-granulated slag. In hot asphalt mixtures used for surface and binder courses,
slowly-cooled slag can be used as a substitute for coarse and fine aggregates, and
water-granulated slag can be used as a substitute for coarse, fine, or crushed sand, which
is used in some cases to replace fine aggregate. The slag can also be used for stability
treatment of hot asphalt.
Water-granulated slag has been more often used as a fine aggregate in hot
asphalt mixture, but results are also available for examples in which slowly-cooled slag
has been used as a coarse material.
The number of examples of the use of molten slag as aggregate in mixtures for
surface and binder courses of asphalt pavement is increasing, and results on its use are
accumulating at a steady rate. However, the verification data with regard to long-term
durability are not sufficient. Also, the traffic volume classification for road design that
has used molten slag in the past has a road-paving design traffic volume of T < 1,000
(vehicle/day/direction).
49
1) Quality Standards and Test methods
Molten slag that is used as coarse or fine aggregate in hot asphalt mixtures must
conform to the quality regulations for the relevant material, as stipulated in the
Construction Guidelines for Pavement Design and Construction, etc.
The quality regulations for hot asphalt mixture that uses molten slag
aggregate must conform to the relevant asphalt mixture regulations stipulated in
the Guidelines for Pavement Design and Construction, etc., depending on the type of
road pavement.
The quality tests stipulated in the quality standards are to be carried out in
accordance with the instructions stipulated in the Guidelines for Pavement Test
Methods.
The environmental safety standards, test methods, and safety management for
molten slag aggregate used for the surface and binder courses of asphalt pavement
must conform to (2) 2) of 1.1.1, Chapter 2 of this manual. In other words, effluent tests
and toxic content tests on six substances must be carried out in order to guarantee
quality.
[Description]
Re: 1) The molten slag used as coarse or fine aggregate in hot asphalt mixtures
must conform to the quality standards for single-size crushed stones and screenings,
depending on the type of road pavement.
The presence of a large amount of iron in molten slag leads to oxidization and
discrepancies in density, so it is desirable to carry out magnetic separation beforehand
to reduce the amount of magnetic material. Moreover, it is recommended for the
improvement of safety of construction procedures and the improvement of particle size
and level that acicular matter in the molten slag be removed and any molten slag
aggregate with sharp edges be rounded-off.
The standard values for asphalt mixture with regard to the Marshall stability
tests stipulated in the Guidelines for Pavement Design and Construction are shown in
Table 1.1.2-1.
The tests for each quality aspect are to be carried out in accordance with the
test methods explained in the Guidelines for Pavement Test Methods. Also, the quality
values for hot asphalt mixtures must satisfy the conditions listed in Table 1.1.2-2. When
50
molten slag aggregate is used on its own as a surface and binder courses material for
pavement, the material used must conform to the regulation on molten slag aggregate
for use on roads (see published Technical Report TR A 0017). The types and names of
the slag used in the surface and binder courses of roads are stipulated in TR A 0017, as
shown in Table 1.1.2-1.
Table 1.1.2–1. Standard Values for Marshall Stability Tests
Mixture Type
Tamping Count
Porosi
Satur
Stabili
Flow
1,000
ty
ation
ty
Value
(%)
(%)
(kN)
(1/100
T<1,000
T
cm)
3–7
(1) Coarse-grade
65–85
4.90
Asphalt Concrete
or
(20)
above
4.90
(2) Dense-grade
Asphalt Concrete
20–40
75
50
or
3–6
(2) (13)
70–85
above
4.90
(3) Fine-graded Asphalt
or
Concrete (13)
(4) Dense- and
3–7
65–85
3–5
75–85
2–5
75–90
above
Gap-grade Asphalt
Concrete (13)
(5) Dense-grade
Asphalt Concrete
(20F) (13F)
(6) Fine-grade
Asphalt Concrete
50
(13F)
(7) Fine-grade
3.43
Asphalt Concrete
or
(13F)
above
51
20–80
3–5
(8) Dense- and
75–85
4.90
20–40
Gap-grade Asphalt
or
Concrete (13F)
above
(9) Open-grade
75
50
―
―
3.43
Asphalt Concrete
or
(13)
above
Note: (1) T: Paving design traffic volume (vehicle/day/direction)
(2) Tamping count of fifty times on areas at small risk of rutting from traffic
flow in heavy-snowfall and cold-climate areas, even when 1,000 T<3,000.
(3) Values in the Stability column: standard values for a tamping
count of seventy-five times when 1,000 T.
(4) It is desirable to attain a residual stability level of 75% or more
with the following equation when it is thought that the admixture will be
easily affected by water and for admixtures that are used in paving in areas
that may be affected by water.
Residual stability level (%) = (60 deg. C, stability level (kN) after
48-hour water penetration / standard stability level (kN)) X 100
Table 1.1.2-2. Types and Quality of Molten Road Slag Used in Wearing Course and
Substratum Layers
Test Method
Type
Absolute
Density
Moisture
Abrasion
Absorption
Loss
Rates
JIS A 1121
JIS A 1110
JIS A 1110
Size-controlled Solubilized and
Solidified Aggregate (Slowly-cooled
Solids), Crusher-run Solubilized and
Solidified Aggregate (Slowly-cooled
2.45 g/cm3 or
above
Solids)
52
3.0% or less 30% or less
Table 1.1.2-3. Types and Names of Slag Used for Surface and Binder Courses of Roads
Type
Name
Application
Single-size Solubilized and
SM–20
For use in hot asphalt
Solidified Aggregate
SM–30
mixture
SM–5
Fine Solubilized and
FM–2.5
For use in hot asphalt
Solidified Aggregate
mixture
(Hydro-pulp Solids,
Slowly-cooled Solids)
Table 1.1.2-4. Particle sizes of Road Slags Used for Surface and Binder Courses
Name
Percentage (%) of Material that Passes Through Metal Sieve
Nominal Size of Sieve Holes (mm)
SM-20
26.5
19
13.2
4.75
2.36
1.18
0.075
100
85‒100
0‒15
―
―
―
―
100
85‒100
0‒15
―
SM-30
―
SM-5
―
―
100
85‒100
0‒25
0‒5
―
FM-2.5
―
―
―
100
85‒100
―
0‒10
As the molten slag used as aggregate in hot asphalt mixture is usually coated with
asphalt after being mixed with other materials, it is acceptable if the slag satisfies the
environmental safety standards for mixtures. However, in taking into consideration the
safety of storage and transportation, etc., of the slag, it is desirable to use slag for which
the manufacturer has implemented environmental safety tests on each slag aggregate lot.
Re: 2) Conforms to Section Two 1.1.1 (2) 2), Chapter 2.
53
3) Technology Used
1) Design
Paving that uses molten slag aggregate as asphalt mixtures for the surface and
binder courses of asphalt must conform to the methods and procedures stipulated in
the Guidelines for Pavement Design and Construction. In addition to the mixtures
generally being usable on roads with a paving design traffic volume of T<1,000
(vehicle/day/direction), as a general principle the amount of molten slag aggregate
included in the mixture must not cause any problems performance-wise.
2) Construction
(1) It must be verified that a sludge slag aggregate can be supplied without fail.
(2) Consideration must be given to avoiding mixing of the sludge slag aggregate with
other materials.
(3) Construction must conform to the ordinary subgrade construction method that
uses ordinary aggregate.
3) Maintenance of Logs, and Repeated Reuse and Disposal
When using molten slag aggregate as a hot asphalt mixture, the purchaser must
store all material investigation records (including test results on molten slag
aggregate), mixture design diagrams, construction plans, and all other
documentation related to construction so that information on the relevant subgrade
material can be used when the subgrade is to be recycled and reused or disposed of.
[Description]
Re: 1) Molten slag aggregate that is used as an admixture for the surface and
binder courses of asphalt must conform to the same methods and procedures as for
ordinary mixtures. However, as a general principle it is to be used on roads with a paving
design traffic volume of T<1,000 (vehicle/day/direction).
Although the number of examples of using molten slag aggregate as an
admixture for the wearing course and substratum layers of asphalt are increasing, these
examples are only from test constructions. Also, as there are no examples of molten slag
aggregate being used on roads with heavy traffic, for the time being it may be used only
for B classification design traffic volumes (paving design traffic volume of 250≦T<1,000).
If it is to be used on roads classified as C for classification design traffic (paving design
traffic volume of 1,000≦T<3,000), then a full series of tests must be carried out
beforehand.
According to the examples of application of molten slag aggregate to asphalt
54
pavement, there are very few verification data regarding long-term durability, but the
results of investigations at the early stage of construction and several months after use
do not show any inferiorities to cases in which an ordinary mixture has been used.
Therefore, the equivalent conversion coefficient for asphalt mixture for surface and
binder courses using molten slag aggregate is set at 1.0. If the mixture is to be used for
asphalt stability treatment the equivalent conversion coefficient is set at 0.8.
As the Marshall stability level, the dynamic stability level, and the stripping
resistance level are lowered when the amounts of molten slag aggregate mixed into the
mixture are increased, it is necessary to give full consideration to the amount of molten
slag blending. The results of past investigations have shown that there is no problem if
molten slag aggregate makes up less than 10% of the whole aggregate.
In addition to initiating surveys to ensure that the required amounts can be
obtained when using molten slag aggregate, it is also necessary to establish a material
usage plan to ascertain that the plan satisfies the prescribed quality standards and other
aspects such as quality performance, productivity, and transportation routes.
Re: 2) The usage of hot asphalt mixture in road construction from molten slag
aggregates must conform to the construction methods stipulated for ordinary hot asphalt
mixture. All construction logs and journals relating to the material used, the design mix
formula, and the construction conditions must be saved and stored as a basic principle for
asphalt pavement that uses molten slag aggregates. The investigations that are initiated
at the time of construction and after construction must include (1) surface smoothness, (2)
cross-sectional views (rutting), (3) skid resistance values, (4) cracking ratio, and (5) visual
road surface inspections, etc.).
Re: 3) As asphalt pavement is ordinarily reused, the repeated use of asphalt
mixture that contains molten slag aggregate becomes a prerequisite condition for reuse. It
is therefore necessary for the purchaser to store all investigation records on materials
used, design mixture formulae, construction plan views, and all other documentation
related to construction so that information on the relevant subgrade material is available
when it is recycled for reuse or disposed of.
Also, when asphalt mixture that uses molten slag aggregates is reused or
disposed of, it is necessary to verify the details of the drawings and specifications for its
initial use and to consult with the manufacturer of the molten slag aggregate to establish
55
suitable methods and procedures.
1) Usage Results
There are some construction records of the use of molten slag in hot asphalt mixtures.
However, this does not mean that records exist for every piece of slag manufactured at
every solubilization processing facility. Therefore, it is necessary to verify each lot
independently. All other conditions are the same as those stipulated in Section Two,
1.1.1 (4).
RE: 1) Several tens of examples of construction results using asphalt mixture
aggregates already exist, but there are very few solubilization processing facilities that
have manufactured molten slag used in asphalt mixture aggregates. It is therefore
necessary to confirm a facility’s production capacity of usable slag beforehand.
References
1) Oi and Kaneko: Use of Molten Slag as Asphalt Mixture in the City of Omiya, Pavement,
Vol. 32, No. 4, 1997
2) Kuroda and Shimoda: Investigation into the Reuse of Molten Slag Asphalt Mixture
Fine Aggregates, 22nd Japan Road Association Thesis Collection, 1997
3) Sazawa and Satake: Use of Asphalt Mixture Containing City Waste Molten Slag on
Actual Roads, 22nd Japan Road Association Thesis Collection, 1997
4) Fukumitsu and Suzuki: Use of Waste Incineration Ash Molten Slag as Asphalt
Mixtures, Road Design, August 1996.
5) Tamura, Fukumitsu and Suzuki: Use of Waste Incineration Ash Molten Slag for
Asphalt Mixture, 21st Japan Road Association Thesis Collection, 1995
6) Kataishi, Nakazawa and Hagiwara: Use of Molten Slag Sand Paving Materials, 21st
Japan Road Association Thesis Collection, 1995
7) Saeki, et al.: Recycling City Waste Incineration Ash (4), Use of Solubilized and Molten
Slag for Asphalt Aggregate, 8th Japan Society of Waste Management Experts’ Collection
of Presented Theses, 1997
8) Nishihara, et al.: Use of City Waste Molten Slag for Asphalt Aggregate, 20th Japan
Waste Management Association’s Collection of Presented Theses, 1999
56
1.1.3. Aggregate for Cast-in-situ Concrete
This section applies to the case in which molten slag aggregate has been obtained by
melting general waste incineration ash and fly ash at temperatures of 1,200 degrees
Celsius or higher and then cooled for use as coarse or fine aggregate in cast-in-situ
concrete.
[Description]
In slag that has been obtained by melting incineration ash at temperatures of
1,200 degrees Celsius or higher, nearly all the chloride compounds have been dissolved,
and there is very little chance of dioxins or other toxics remaining in the residue. The
physical and chemical properties of molten slag aggregates differ greatly, depending on
the composition of the incineration ash and the melting and cooling methods or the like.
Even if they seem like solid crushed stone or crushed-sand slag, this does not guarantee
that they can be used as aggregate and will cause no problems with the concrete.
However, tests may be performed when crystallized molten slag that may be adequate
for use as aggregate in cast-in-situ concrete is being manufactured; if the test results
show that the mixture satisfies the quality and performance conditions required for the
relevant concrete aggregate, then it can be used for cast-in-situ concrete.
（2）Test Evaluation Methods
The physical qualities of molten slag aggregate used for cast-in-situ concrete must be
equal to or above those required by JIS A 5005, “Crushed Stone for Concrete”, crushed
sand and the like. The quality testing methods for verifying performance are stipulated
in the same regulations.
The environmental safety standards, test methods, and safety management methods
for molten slag aggregate used for cast-in-situ concrete are to conform to the
stipulations laid down in 1.1.1 (2) 2), Chapter 2. In other words, effluent tests and toxic
content tests on six substances are to be performed. If the molten slag for concrete is
regulated by JIS standards, then these must be followed.
[Description]
RE: 1) Molten slag aggregate manufactured from incineration ash and sewage
sludge is not regulated in the regulations of the Japan Society of Civil Engineers’
Standard Specifications for Concrete (hereinafter referred to as the Concrete
Specifications,) but there is regulation of the use of blast furnace slag and ferronickel
slag as aggregate. Regulation of the use of molten slag aggregate manufactured from
57
incineration ash or sewage sludge as concrete aggregate is currently being considered
for inclusion in the JIS standards.
The results of investigations carried out by the Japan Concrete Institute (JCI)
have been published as proposed JCI regulations. For the performance required of
concrete aggregate that uses molten slag, these proposals use the same regulated values
as the current ones used for crushed stone or crushed sand. This manual therefore uses
the values shown in Table 1.1.3-1 as quality standards for molten slag aggregate. In
other words, as long as the physical and chemical properties of the molten slag
aggregate satisfy the values listed in Table 1.1.3-1, then the molten slag aggregate can
be used as both coarse and fine aggregates.
58
Table 1.1.3-1. Quality Standards for Molten Slag Aggregate
Classifi
Item
cation
Molten Slag
Molten Slag
Coarse
Fine Aggregate
Aggregate
(Test Method)
(Test Method)
Chemic Calcium oxide (Ca0
45.0 or less
45.0 or less
al
value)
(JIS A 5011)
(JIS A 5011)
Conten
Total sulfur (S value)
2.0 or less
2.0 or less
(JIS A 5011)
(JIS A 5011)
t (%)
Sulfur trioxide (SO3
0.5 or less
0. 5 or less
value)
(JIS A 5011)
(JIS A 5011)
Metallic iron (Fe value)
1. 0 or less *
1.0 or less *
(JIS A 5011)
(JIS A 5011)
0.04 or less
0.04 or less
(JSCE-C 502)
(JSCE-C 502)
Chloride (NaCl value)
Physic
Absolute dry density
2.5 or less
2.5 or more
al
g/cm
(JIS A 1110)
(JIS A 1109)
Proper
Moisture absorption %
3.0 or less
3.0 or less
(JIS A 1110)
(JIS A 1109)
12 or less
10 or less
(JIS A 1122)
(JIS A 1122)
Particulate shape
55 or more **
53 or more **
decision rate %
(JIS A 5005)
(JIS A 5005)
Abrasion loss
40 or less
―
３
ties
Stability loss %
(JIS A 1121)
Volume lost during
1.0 or less
7.0 or less
aggregate fine
(JIS A 1103)
(JIS A 1103)
particle volume
test %
* Applied when color of the surface is especially important. ** In the event that the slag
does not satisfy these conditions independently, it can still be used if mixed with other
aggregate and satisfies the conditions.
There are certain types of molten slag aggregate that have been verified, and
for these the alkali aggregate reaction test (JIA A 1145 or 1146) is implemented
similarly to that for ordinary aggregates. However, when it is not possible to confirm
59
non-toxicity by the alkali aggregate test, the total alkali content is restricted to 3.0
kg/m3. It is possible to use molten slag aggregate if non-toxicity measures, such as
turning cement into blast furnace cement, are taken. These measures are described in a
notification released by the Ministry of Land, Infrastructure, and Transportation and in
the JIS standards and are implemented for natural aggregates.
One of the methods used for improving the quality of molten slag aggregate is
to re-heat slag that has been air-cooled and solidified and to then recrystallize it in a
rotary kiln or the like.
Re: 2) Conforms to the descriptions provided in 1.1.1 (2) 2), Chapter 2.
(3) Technology Used
1) Design Methods
(1) The design strength of concrete when molten slag aggregate is used in a concrete
building is generally set as 24 N/mm２or less. However, when molten slag is used in
reinforced concrete, it is necessary to use molten slag aggregate that has been used in
concrete buildings or whose performance has been certified by a public organization.
(2) The water to cement ratio for cement that requires durability is 55% or less.
(3) When freeze-damage resistance is required, the freeze-damage resistance levels of
the concrete compound must be verified with tests.
2) Construction Methods
(1) It is necessary to check whether the molten slag aggregate can be supplied without
fail.
(2) It is necessary to carefully check that molten slag aggregate will not be mixed up
with ordinary aggregate.
(3) The construction method must conform to construction methods that use ordinary
aggregate.
3) Maintaining Journals and Logs
When molten slag aggregate is used, it is necessary to record that fact in the
design mix formula and other documents.
[Description]
Re: 1)
(1) Even when molten slag aggregate is used, the same level of strength as for concrete
that uses natural aggregate is displayed. Therefore, it seems unnecessary to set the
upper limits of concrete strength. However, as there are very few results in which
molten slag aggregate has been used or cast-in-situ, usage should be restricted to
non-reinforced concrete and reinforced concrete that does not require high levels of
60
strength. Concrete with a standard strength of between 21 and 24 N/mm２ is widely
used in constructions by the Ministry of Land, Infrastructure, and Transport, such as
street gutters, building foundations, retaining walls, and concrete frames. Molten slag
can also be used in low-strength concrete to be used for uniform concrete and backfill.
(2) The water to cement ratio of cement that is made from molten slag aggregate and
requires freeze-damage resistance is 55% or less.
(3) Differences in the quality of molten slag aggregate are shown in its durability when
it is frozen and then thawed. When molten slag aggregate for which few examples of use
are available is used in areas that are subject to freeze-damage, the freeze-damage
resistance capabilities of the concrete must be confirmed by freeze-thaw tests before use.
The quality of molten slag aggregate with low freeze-damage resistance can be
improved by mixing it with a good-quality natural aggregate.
Re: 2) As there are very few results on the production volumes and uses of
molten slag aggregate, it is necessary to carry out a thorough investigation into whether
molten slag with appropriate levels of quality can be supplied without fail. If the molten
slag aggregate satisfies the quality standards stipulated in Table 1.1.3-1 by itself, then
it can be used on its own. However, mixing it with a good-quality natural aggregate
eradicates the color and shape that is unique to molten slag, and it can be used for
construction in the same way as natural aggregate is used. It is therefore a good idea to
mix it with a natural aggregate to as great an extent as possible when limited supplies
of molten slag aggregate exist. Note, however, that there are types of concrete in which
the use of molten slag aggregate is not accepted, so it is necessary not to mix the molten
slag aggregate with ordinary aggregates when stocking them.
As size-controlled slag aggregate can be used to manufacture fresh concrete
with almost the same properties as ordinary concrete, it is possible to apply the same
construction methods as are used for concrete that uses ordinary aggregate.
Re: 3) As we need to accumulate information on the durability and the like of
concrete structures that use molten slag aggregate, records of the parts of the building
in which molten slag aggregate has been used, the aggregate manufacturer, the design
mix formula for the concrete, and other information must be created as construction
logs and stored accordingly.
When concrete that uses molten slag is to be dismantled and reused as soil
material or concrete aggregate, the usage methods can be determined by referring to the
usage standards of recycled aggregate.
61
Inspections into quality must be implemented before use. When aggregate is to be used
in structural members, it is necessary to choose aggregate whose performance levels
have been verified by a public organization.
2) Usage Results
Molten slag aggregate has been very rarely used in cast-in-situ concrete. An aggregate
whose performance levels have been confirmed must be selected.
3) Supply
There are many regions that do not produce molten slag, and very little makes it to the
open market when it is produced. Therefore, it is necessary to implement surveys of
the possibility of obtaining the aggregate required.
Although when molten slag is used as concrete aggregate no more carbon dioxide is
emitted during construction than is emitted during the production of ordinary
concrete, the fuel used during the manufacture of molten slag emits large quantities of
carbon dioxide.
[Description]
Re: 1)
The Japan Concrete Institute and other organizations have proposed several
regulations on the properties required for molten slag aggregate used for concrete
aggregate, but it is acceptable to use the standards stipulated in this manual. The most
important points are to ensure the use of aggregates manufactured by plants that
adhere rigidly to these standards in their quality management on a daily basis. It is
recommended that aggregate plants whose quality has been checked and authorized by
another plant constantly manufacturing slag aggregates, or by a public organization or
the like, are designated, and that the aggregates produced by such approved plants are
used.
Re: 2)
Results are available for use in actual construction projects４）, but the number of
examples is extremely small.
Re: 3)
Fine molten slag aggregate can be supplied from Tokyo, etc. Details on the required
quality and performance levels are to be discussed with the contractor.
Re: 4)
62
Although molten slag used as concrete aggregate does not emit more carbon dioxide
than ordinary concrete during construction, the fuel used during the manufacturing of
molten slag emits large quantities of carbon dioxide.
Molten slag aggregate is manufactured by being melted at temperatures of 1,200
degrees Celsius or higher, so environmental safety can be verified by implementing the
tests on six substances.
(2) Repeated Use
The concrete can be reused by crushing it and then using it as low-quality concrete
aggregate. As it is used in low-quality concrete, the reuse of the molten slag is not
deemed to be a problem.
(3) Financial Viability
The cost of producing molten slag is assumed to be several tens of thousands of yen per
ton, but the market price is not determined by product cost but by supply and demand.
For example, in the city of Togane in Chiba Prefecture, fine molten slag aggregate is
sold for ¥200 per ton.
There is no difference between the construction methods used with concrete made with
molten slag and concrete made with ordinary aggregate.
(4) Necessity
Molten slag production is an excellent technology that detoxifies general incineration
ash. Once the production of molten slag gathers momentum it will be possible to
produce it in vast quantities, and it will become necessary to use it in fields that require
high-volume consumption, such as in concrete materials usage.
[Reference]
1) Ministry of Economy, Trade and Industry: Technical Report (TR A 0016:2002) Fine
Concrete Aggregates that Use Solubilized and Solidified General Waste and Sewage
Sludge, Japanese Standards Association
2) Outline of the JCI Standards (Proposed) for Molten Slag Aggregates Produced from
General Waste and Sewage Sludge and Crushed Stone Dust, TR Proposal, Japan
Concrete Institute, Vol. 29, No. 12, December 2001
3) Environmental Bureau of the Tokyo Metropolitan Government: Guidelines for
Recycling Molten Slag Resources in Tokyo Metropolitan City, March 2001
4) Wataru Natsuhori: Use of Molten Slag for Small-scale Concrete Retaining Wall
Foundations and Aggregate, Kanto 2001 Skill-Up Seminar, March 2001
63
1.1.4 Aggregate for Factory-Produced Concrete
This section applies to molten slag that has been obtained by melting general
incineration ash and fly ash at temperatures of 1,200 degrees Celsius or higher and
then cooling it for use as coarse aggregate or fine aggregate in factory-produced
concrete.
[Description]
Nearly all the chloride compounds in slag that has been obtained by melting
incineration ash at temperatures of 1,200 degrees Celsius or higher have been dissolved,
and there is very little chance of dioxins or other toxics remaining in the residue. The
physical and chemical properties of molten slag aggregate differ greatly, depending on
the composition of the incineration ash and on the melting and cooling methods or the
like. This has already been explained in the section on aggregate used in cast-in-situ
concrete.
To conform to 1.1.3 (2), Chapter 2.
[Description]
As the performance demanded of the aggregate used in factory-produced
concrete is basically the same as that demanded of aggregate for cast-in-situ concrete,
the molten slag must satisfy the quality standards stipulated in Table 1.1.3-1. There
are some cases in which the applications and environment in which some
factory-produced concrete is to be used are restricted. Some products are laid in
underground locations where they are not affected by freeze-damage, etc., whereas
other products are free from abrasion or others are used as products that can be
replaced.
Therefore, in the case of certain factory-produced products, when it is
confirmed that the complete product satisfies the required performance levels,
aggregates that do not completely satisfy the chemical properties and physical
characteristics stipulated in Table 1.1.3-1 may be used as long as it can be confirmed
that they satisfy the performance levels demanded of complete products.
(3) Technology Used
1) Design Methods
(1) The design strength of factory-produced concrete that uses molten slag aggregate
must satisfy the quality levels required of the product. However, in the case of
high-strength concrete and reinforced concrete, it is necessary to use molten slag
aggregate that has accumulated favorable production results, or for which the
64
performance levels of the product have been certified by a public organization.
(2) The water-cement ratio of concrete must be 55% or less.
(3) When freeze-damage resistance is required, the freeze-damage resistance levels
of the concrete compound must be verified with tests.
(1) When molten slag aggregate is used in a product, the product must be verified as
satisfying the specific performance levels of that product.
(2) It is necessary to be careful not to mix up the products that use molten slag
aggregate with ordinary aggregate.
(3) The construction method using products containing molten slag aggregate should
conform to the methods used for ordinary products.
3) Maintaining Journals and Logs
When factory-produced products using molten slag aggregate are used, it is
necessary to keep a record of this fact.
[Description]
Re: 1) (1) Aggregate that uses molten slag is also available with a hard
consistency, and because its use in rich concrete mixes gives these mixes great strength,
it is possible to use it in various concrete products, such as interlocking blocks, concrete
slabs for paving, concrete barrier blocks, building blocks, tiles, concrete pipes, and
bricks. Specifications exist for the test methods and strength of such concrete products,
and the performance of products that use molten slab aggregate must therefore conform
to the stipulated regulations.
(2) As concrete with a low water to cement ratio is most effective for producing concrete
with high levels of durability, it is desirable to set a small water to cement ratio of 55%
or less when molten slag aggregate is used.
(3) The quality of molten slag aggregate is prominently displayed in its freeze-damage
resistance levels. When molten slag aggregate for which few examples of use in areas
that are subject to freeze-damage are available is to be used, the performance of the
product in freeze-thaw tests should be checked prior to use.
Re: 2) (1) As production volumes and actual usage of molten slag aggregate are
very small, it is necessary to check whether a supply of molten slag aggregate that has
the required levels of quality is available. If the molten slag aggregate satisfies the
quality standards stipulated in Table 1.1.3-1 by itself, then it can be used independently.
However, there are cases in which the particle size or shape of molten slag aggregate
differs slightly from that of ordinary aggregate. Even in such cases, the molten slag
aggregate may be used if it satisfies the standards when mixed with natural aggregate.
65
It is necessary, however, to make sure that those products are not mixed with concrete
in which the use of slag aggregate is not authorized.
(2) In the event that the product in which molten slag aggregate is used is not a JIS
product, then it is necessary to make sure that the product is not mixed together with
JIS products.
(3) The performance of the product that uses molten slag must be constructed in a
manner that satisfies the regulations required of ordinary materials. It is therefore
possible to use such products in the same way as ordinary products are used.
Re: 3) It is necessary to accumulate information on the durability and the like
of structural objects that use molten slag aggregate, so it is desirable to store all
construction records, including information on the parts for which the product is used,
The problems with aggregate are the same as those listed for aggregate used for
cast-in-situ concrete.
2) Usage Results
There are great differences in the actual usage results for factory-produced concrete
products made from molten slag, depending on the region. It is therefore desirable to
select aggregate that has been manufactured by plants whose products made from
molten slag have already been used.
3) Supply
There are many regions in which molten slag is not produced. It is therefore necessary
to check whether it is possible to obtain the required amounts of aggregate.
Although the manufacture of concrete products does not emit great volumes of carbon
dioxide, because of the usage of the fuel used during the manufacturing process large
quantities of carbon dioxide are emitted.
the construction method, and the manufacturer and design mix formula, together with
all other construction records.
[Description]
Re: 1)
The required performance levels of molten slag aggregate used in concrete have been
stipulated in the Japan Concrete Institute Standards and in JIS TR A 0016 and are
currently being investigated for inclusion in the JIS standards. Although the methods of
use suggested in this manual are based on the most strictly regulated methods derived
66
from these documents, no problems are expected if usage is based on the JIS standards,
which are to be announced in future. It is desirable to use products that are
manufactured by factories that observe strict quality management policies on a daily
basis.
The most important point is the quality of each individual product that has been factory
produced. If it can be confirmed that the quality of factory-produced products made from
slag aggregate is better than the quality of factory-produced products made from
ordinary aggregate, then it is not necessary to demand high-level physiochemical
properties and performance of the material used.
Re: 2)
As can be seen from the examples below, there are many usage results for interlocking
blocks and other factory-produced products. In addition to interlocking blocks, there are
also examples of the use of factory-produced box culverts and L-shaped retaining walls.
Re: 3)
The details already explained for molten slag aggregate used in concrete apply here.
Similarly to the case of molten slag aggregate for concrete, there is very little production
of factory-produced products.
Re: 4)
Although the use of molten slag in factory-produced products does not emit excessive
amounts of carbon dioxide, the fuel used during the manufacturing of molten slag emits
2.4 tons of carbon dioxide for each ton of slag.
Molten slag aggregate is manufactured by being melted at temperatures of 1,200
degrees Celsius or higher, so environmental safety can be verified by implementing the
tests on six substances.
(2) Repeated Use
There are cases in which concrete structural objects are dismantled and the contained
molten slag is used as aggregate. There is deemed to be no problem with reusing the
this molten slag in low-quality concrete, but it is necessary to carry out investigations to
ascertain whether the molten slag aggregate is applicable or not for reuse.
(3) Economic Viability
The cost of producing molten slag is high, but market prices are not dictated by
production costs. It is thought that construction costs will be approximately the same as
when ordinary aggregate is used.
(4) Necessity
67
Molten slag production is an excellent non-toxic technology that uses general
incineration ash. However, molten slag must be used in fields that require high-volume
consumption. There is therefore a necessity for the molten slag to be used as a
construction material for concrete, etc.
[Product Examples]
1) Interlocking blocks that use city waste incineration slag (Matsuo Corporation)
2) Interlocking blocks and calcinated tiles that use molten slag (Kubota Corporation)
3) Recycled ceramic blocks (Azmic Tohoku Corporation)
4) Water-retaining recycled blocks (Tsurumi Manufacturing Co., Ltd)
5) Paving stones recycled from waste incineration ash (Toyo Color Corporation)
[Reference]
Construction Research Institute: Handbook on Recycled Resources for Use in
Construction, December 2000
1.1.5. Backfill
This section applies to the backfill procedures that use general waste and incineration
ash molten slag.
[Description]
As there are no strict regulations regarding its physical characteristics (with the
exception of particle size), backfill material is a suitable application for molten slag, as
long as the backfill material satisfies the environmental safety standards.
The maximum diameter of the molten slag particles used in backfill soil must be 50
mm or smaller, and there must be 25% or fewer fine particles with a diameter of 0.075
mm or less. The tests to determine the proportion of fine particles included are carried
out in accordance with JIS A 1204 or JGS 0135.
The environmental safety standards, test methods, and safety management policies for
molten slag used in backfill must conform to the stipulations laid out in 1.1.1. (2) 2),
Chapter 2.
[Description]
68
Re: 1) The performance levels expected of backfill material are listed below.
a) Compression
Material with low compaction rates must be used to prevent gaps and unevenness
appearing between the backfill and the buried structural object after it has been laid. It
is also necessary to compact it thoroughly.
b) Effects on Buried Structures
Standards exist to regulate the maximum diameter of the particles contained in backfill
material. These standards have been enacted to prevent the backfill from damaging the
buried structures, so it is necessary to verify the maximum particle diameter and make
sure the conditions are satisfied before use.
c) Bearing Value and Constructability
It is necessary to improve compression constructability and water drainage capabilities
in order to raise the bearing value. It is therefore important to ensure that the
regulations regarding the proportion of fine particles are satisfied.
d) Malformation and Fluxion Caused by External Force
Depending on the structure, there are cases where the strength after compression with
CBR, etc., is regulated. So the molten slag used must satisfy these stipulations after it
has been compacted.
Re: 2) Conforms to the descriptions provided in Section Two 1.1.1. (2) 2). The
six effluent tests and toxic content tests on six substances are to be carried out.
(3) Technology Used
1) Air-cooled slag is used as a substitute for crusher-run and pit-run gravel, etc.
2) Water-granulated slag is used as a substitute for sandy soil and sand.
3) The slag may be mixed with natural material to improve the particle size.
4) The compression rate (Dc) must be 90% or higher when the slag is to be compacted
for use.
[Description]
Although both air-cooled slag and water-granulated slag efficiently satisfy the
strength conditions and other physical properties as backfill materials, there are many
cases in which particle size distribution is so bad that it is not possible to achieve the
required density for the necessary level of compression when the slag is used
Conforms to the details explained in Section Two, 1.1.1 (4).
independently. In this event, the compression levels are improved by mixing the slag
with naturally produced aggregate and then subjecting it to stabilization.
[Description]
69
Conforms to the details explained in Section Two, 1.1.1 (4), Chapter 2.
[Examples of Usage]
Examples of usage are shown in Tables 1.1.5-1 and 1.1.5-2.
Table 1.1.5-1. Use of Molten Slag as Backfill Material, Example #1
Use
Backfill Material (1)
Client
Tokyo City
Processed
Incineration ash
Incineration ash, fly
Incineration ash, fly
Material
(stoker)
ash (stoker)
ash (stoker)
Furnace
Arc-type
Fixed surface
Plasma-type
Type
Slag Type
Abiko City
Matsuyama City
melting-type
Water-granulated slag Water-granulated
slag
Quantity
2,000 (fiscal year
(tons)
1995)
Usage
Used by itself
Water-granulated
slag
370 (fiscal year 1995) 5,122 (fiscal year
1995)
Mixture of 50% pit
sand and 50% molten
slag for water pipe
and sewerage pipe
construction
Mix Ratio
100%
100%
Main Place
Central Breakwater
Abiko Waterworks
Landfill Site
Department, Sewage
of Use
Section
Stage of Use Used for tests
Problems
Needed to be mixed
As water-granulated
with earth and sand,
slag was used, it had
as surface compression
less strength in
was unacceptable
comparison with
when the slag alone
sand, etc.
was used.
Remarks
Backfill material
Soil covering at final
disposal site
70
Table 1.1.5-2. Use of Molten Slag as Backfill Material, Example #2
Location
Tohoku
Work Involved
Recycled Material
Public road #45
General
repair work
incineration ash
(molten slag)
Chugoku Public road #30
road-widening work
Water-granulated
slag
Use of Recycled Materials,
etc.
- Recycled asphalt compound
aggregate.
- Used as protective sand
during the construction of a
public road information box.
- Countermeasure for soft
ground during road-widening
work.
[Reference]
1) Japan Waste Research Foundation: Research into the Appropriate Processing and
Effective Use of Incineration Ash, Fiscal Year 1996 Report (Reference Material),
September 1997
2) Japan Society of Industrial Machinery Manufacturers: 1999 Survey into the Use of
Eco-Slag (Part Two, Survey on Distribution Systems), June 2000
3) Japan Society of Industrial Machinery Manufacturers: 2000 Survey into the Use of
Eco-Slag (Part Three, Aiming for Widespread Use in the 21st Century), June 2001
4) Shinichi Kai, Junichi Miyake, Keiji Iguchi, and Shotaro Sasaki: Report on Surveys into
Recycled Molten Slag in the Waste Material Power Generation Industry, Japan Society of
Waste Management Experts, 12th Japan Society of Waste Management Experts’
Collection of Theses, pages 549 to 551, 2001
5) Masato Oka, Takeo Katami, Yu Yasuda, et al.: Evaluation of Environmental Effects
when Molten Slag is Used as Public Works Resources, Japan Society of Waste
Management Experts, 12th Japan Society of Waste Management Experts’ Collection of
Theses, pages 561 to 563, 2001
6) Koji Kusu, Masami Sakai: Proposal for Fundamental Quality Control Policies for
Promotion of Effective Use of Slag, Japan Society of Waste Management Experts, 12th
Japan Society of Waste Management Experts’ Collection of Theses, pages 552 to 554,
2001
7) Kiyoshi Takai, Kosuke Murai, Manatsuru Umemoto, Kazuhiko Oka, et al.: Suitability
of City Waste Incineration Molten Slag (Crystallized) as Coarse Aggregate for Concrete,
Japan Society of Waste Management Experts, 12th Japan Society of Waste Management
Experts’ Collection of Theses, pages 536 to 538, 2001
8) Construction Research Institute: Handbook of Recycled Resources for the Construction
Industry, December 2000
71
1.2. Calcination Processing (Process for Making Cement)
(1) Overview
Work is proceeding in an effort to reduce the amount of city waste through
efforts to reduce volumes at incineration plants However, issues such as insufficient
processing capacity at incineration plants, reduction in available landfill space, and
environmental pollution are becoming major social problems.
The recently-developed eco-cement uses the incineration ash from city waste
(including incineration ash from sewage sludge) that is calcinated at temperatures of
1,300 degrees Celsius or higher as a recycled resource. In addition to dissolving the
dioxins and other toxic organic matters contained in incineration ash or the like, the
calcination process also enables lead and other heavy metals to be collected as chlorides.
Therefore, this technology is expected to become widespread for relieving the burden of
waste processing and improving levels of environmental safety. Although JIS
standardization of eco-cement is already under way, only a short period of time has
passed since these standards were inaugurated, and the standards for use of eco-cement
have not been sufficiently distributed. For this reason, this manual sets out to provide
additional information on these standards.
(2) Manufacturing Process for Eco-Cement
The method of manufacturing eco-cement is basically the same as that for
manufacturing Portland cement, and the methods of process management and quality
control are also the same. An outline of these processes is shown in Fig. 1.2-1.
Cyclone
Activated coke tower
Bag filter
（
Incineration
ash
Sewage
sludge
Air
）
Refinery
Blending material
Heavy metal collection facility
Cooling tower
Discharge water
Rotary kiln
Natural supplementary material
Recycled heavy oil
Clinker cooler
Air
Bag filter
Air
Gypsum
Clinker tank
Eco-cement
Shipping
Crusher Machine
72
Fig.1.2-1. Manufacturing Process for Calcinated Crushed Cement
1) Raw Material Process: The raw materials blended to make eco-cement are city waste
incineration ash, sludge incineration ash, or the like into which limestone, clay, or other
natural materials are mixed, and the chemical properties of the mix are then adjusted
in a blending tank so that hydraulic minerals are generated. The chemical properties of
the raw material are controlled through fluorescent X-ray analysis.
2) Calcination Process: The blended material, whose chemical properties have been
adjusted, is incinerated in a kiln at approximately 1,300 degrees Celsius or higher, and
clinker is then produced while controlling the calcination level. The gas emitted from
the kiln is rapidly cooled by approximately 200 degrees Celsius in a cooling tower to
prevent the broken-down dioxins from reforming. Most of the heavy metals are also
gasified as chlorides during this process, and once they have been turned into exhaust
gases they are solidified into dust by cooling and then gathered together and collected in
the bug filter, together with the alkaline chloride.
3) Finishing Process: The clinker manufactured during the calcination process is mixed
with gypsum and crushed in a crusher, and the particle size and mixed quantity of
gypsum are then adjusted to produce cement.
(3) Types of Eco-Cement and Their Uses
Eco-cement is categorized into two types: ordinary eco-cement that has had its chloride
ion volume reduced to less than 0.1% by the use of dechlorination technology, and
rapid-cure eco-cement with a chloride ion volume between 0.5% and 1.5%.
The chloride ion contained in the raw cement is collected, together with the dust from
the process of manufacturing clinker for ordinary eco-cement, reducing its volume to
0.1% or less of the cement mass. The minerals are the main components of the clinker
are the same as those in ordinary Portland cement, such as 3CaO/SiO2 (indicated as
C3S), 2CaO/SiO2 (indicated as C2S), 3CaO/Al2O3 (indicated as C3A), and
4CaO/Al2O3Fe2O3 (indicated C4AF), and the eco-cement also shows almost the same
physical properties as ordinary Portland cement, which is regulated under JIS R 5210
“Portland Cement”１）２）.
Rapid-cure eco-cement contains 11CaO/7Al2O3/CaCl2 (indicated as C11A7･CaCl2) as its
calcium-aluminate clinker mineral, and all other components are the same as in
ordinary Portland cement. The hydration speed of C11A7･CaCl2 is extremely fast,
drastically shortening the amount of time required for construction. It is possible to
control the amount of time by appropriately using oxy-carboxylic acid retardant３). As
73
rapid-cure eco-cement contains large amounts of chloride ion, its use is restricted to that
of plain concrete, but its speed of solidification makes it suitable as a concrete for use in
factory-produced products and rapid construction works.
(4) Quality
Examples of the chemical properties of eco-cement are shown in Table 1.2-1, and the
minerals contained in eco-cement are shown in Table 1.2-2. One of the main chemical
properties of city waste incineration ash and sewage sludge incineration ash is that they
contain large amounts of aluminum and chloride components in comparison with the
clay used as the raw material for cement. Consequently, if these waste materials are
used as raw materials in large quantities, the cement will have large aluminum and
chloride components.
The volume of chloride ion in ordinary eco-cement is reduced to 0.1% or less by the
calcination process, and the cement clinker contains more C3A than ordinary Portland
cement. On the other hand, rapid-cure eco-cement contains larger quantities of chloride
cement, and the calcium aluminate clinker mineral C3A becomes C11A7/CaCl2.
Table 1.2-1. Chemical Properties of Eco-cement (%)
ig.loss
Type
SiO2
Fe2O3 CaO
Al2
O3
Ordinary
1.05
16.95
Mg
SO3 Na2
O
7.96
4.40
61.04
1.84
3.86
K2
O
O
0.28
0.02
Eco-cement
Rapid cure
0.05
3
0.73
15.26
9.95
2.47
57.33
1.78
8.79
0.56
0.02
Eco-cement
Ordinary
Cl
0.76
0
0.50
21.92
5.31
3.10
65.03
1.40
2.00
0.31
0.48
Portland
0.00
6
Cement
Table 1.2-2. Minerals Contained in Eco-cement (%)
Type
C3S
C2S
C3A
C4AF
C11A7/CaCl2
Ordinary Eco-cement
49
12
14
13
0
Rapid-cure Eco-cement
46
9
0
8
17
Ordinary Portland Cement
53
23
8
10
0
The quality regulations for eco-cement are shown in Table 1.2-3. The
compression strength of ordinary eco-cement is the same as for JIS R 5210 “Ordinary
Portland Cement”. However, in comparison with the ordinary Portland cement
available on the open market, the actual compression strength is slightly lower. The
strength of quick-dry eco-cement one and three days after use is emphasized, and the
74
values are stipulated close to the ratings for high early-strength Portland cement.
Ordinary eco-cement contains more of the clinker mineral C3A than ordinary
Portland cement and is finer, which means that it has 3.0% more sulfur trioxide than
ordinary Portland cement. Anhydrous gypsum is added to rapid-cure eco-cement,
depending on the amount of clinker mineral C11A7･CaCl2 contained therein, but the
maximum amount of sulfur trioxide to be contained is regulated to prevent too much
anhydrous gypsum from being added.
The amount of chloride ion included is approximately 0.05%, which is slightly
more than the maximum 0.02% that is regulated for JIS R 5210 “Portland Cement”. The
performance of concrete that uses eco-cement is approximately the same as that of
concrete using ordinary Portland cement.
Table 1.2–3. Eco-cement Quality
Type
Quality
Density g/cm3
Ordinary Eco-cement
Measured
Rated
Measured
Rated
Examples
Value
Examples
Value
3.18
Specific Surface Mass
4,100
cm2/g
Aggre
Rapid-cure Eco-cement
−
2,500 or
3.13
5,300
more
Beginning h-m
2–21
gation
more
1–00 or
−
3–29
10–00 or
0–20
less
Stabili
Butt method
Good
ty(4)
Le Chatelier
−
Good
Good
10 or less
−
1d
1–00 or
Good
10 or
less
−
−
23.6
ession
15.0 or
more
3d
24.9
12.5 or more
30.6
th
N/mm2
−
less
Method mm
Streng
3,300 or
more
End h-m
Compr
−
22.5 or
more
7d
35.2
22.5 or more
35.0
25.0 or
more
28 d
52.4
42.5 or more
48.6
32.5 or
more
Magnesium Oxide %
1.84
5.0 or less
1.78
5.0 or
less
75
Sulfur Trioxide %
3.86
4.5 or less
8.79
10.0 or
less
Ignition Loss %
1.05
3.0 or less
0.73
3.0 or
less
Total Alkali % (5)
0.29
0.75 or less
0.56
0.75 or
less
Chloride Ion % (6)
0.053
0.1 or less
0.5∼1.5
0.76
Even if the city waste incineration ash and sewage sludge used as the raw
material for eco-cement clinker contains heavy metals and dioxins in the form of organic
properties, the majority of the lead, copper, cadmium, mercury, and other heavy metals
that it contains is separated from the cement clinker in the form of chloride during the
incineration process at temperatures exceeding 1,300 degrees Celsius, and this is then
cooled and collected in the bug filter, together with alkali chloride as dust. Also, toxic
organic matter, such as dioxins, is dissolved at temperatures that exceed 800 degrees
Celsius during the calcination process, so it does not remain as residue in the exhaust
gas, dust, or cement clinker. Mortar and concrete test samples that use eco-cement are
crushed to particles smaller than 2 mm in accordance with the stipulations laid down in
the Environmental Quality Standards for Soil Pollution (August 23 1991, Ministerial
Announcement No. 46, Ministry of Environment ) and effluent tests are carried out on the
trace components. Table 1.2-4 compares the results of effluent tests carried out on 28-day-old
mortar test samples manufactured in accordance with JIS R 5201 against the standards
stipulated in the Environmental Quality Standards for Soil Pollution (Soil Environment
Standards) and the water quality standards based on Article 4 of the Water Supply Law.
Table 1.2-4. Results of Effluent Tests Carried out on Ordinary Eco-cement Mortar (Aged
28 Days)
Cement
Type
Ordinary
Eco-Cem
ent
Cd
<0.00
5
CN
Pb
Cr6+
ND
<0.01
<0.02
None
0.01
0.05
T-Hg
Cu
<0.000
<0.0
5
1
0.0005
−
As
Se
B
F
<0.01
<0.005
<0.05
<0.4
0.01
0.01
1.0
0.8
Soil
Environ
ment
0.01
Standar
76
ds
Water
Quality
Standar
0.01
None
0.05
0.05
0.0005
1.0
0.01
0.01
1.0
0.8
ds
[Remarks]: “ND” refers to less than maximum detection levels. The inequality symbol refers to
less than maximum amounts. The units used for each value are mg/l.
The concrete design mix formula and physical property values are shown in
Table 1.2-5, and the results of effluent tests on concrete samples aged 28 days are shown
in Table 1.2-6.
Table 1.2-5. Ordinary Eco-cement Concrete Blends and Physical Property Values
Cement Type
Target
W/C
s/a
Slump
(%)
(%)
AE
Slu
Agent
mp
(C x %) (cm)
Air
Compression
Conte Strength at
nt
28 Days
(％)
(N/mm2)
45.0
42.0
0.0055
6.0
4.6
50.9
55.0
44.0
0.0050
6.0
4.3
37.6
Ordinary
65.0
46.0
0.0050
7.5
4.5
28.8
Eco-cement
45.0
44.0
0.0050
16.5
4.1
47.5
55.0
46.0
0.0050
16.5
4.5
34.6
65.0
48.0
0.0050
18.0
4.7
24.6
8 cm
18 cm
77
Table 1.2-6. Results of Effluent Tests on Concrete that Uses Ordinary Eco-cement (Aged
28 Days)
Cement
Slu
Type
mp
W/C %
45.0
Cd
Pb
Cr6+
<0.001
<0.005
<0.001
<0.005
0.002
<0.005
<0.001
<0.005
<0.001
<0.005
<0.001
<0.005
0.01
0.01
0.05
0.01
0.05
0.05
<0.00
1
8 cm
55.0
1
65.0
Ordinary
<0.00
<0.00
1
Eco-ceme
45.0
nt
18
cm
<0.00
1
55.0
<0.00
1
65.0
<0.00
1
Soil Environment
Standards
Water Quality Standards
T-Hg
As
Se
B
F
<0.001
<0.001
<0.05
<0.4
<0.001
<0.001
<0.05
<0.4
<0.001
<0.001
<0.05
<0.4
<0.001
<0.001
<0.05
<0.4
<0.001
<0.001
<0.05
<0.4
<0.001
<0.001
<0.05
<0.4
0.0005
0.01
0.01
1.0
0.8
0.0005
0.01
0.01
1.0
0.8
<0.000
5
<0.000
5
<0.000
5
<0.000
5
<0.000
5
<0.000
5
[Remarks]: The inequality symbol refers to less than maximum amounts. The units used for
each value are mg/l.
Rapid-cure eco-cement is used for mortar and plain concrete products that can make
the best use of its quick-drying capabilities. The results of effluent tests carried out on
mortar samples that were manufactured in accordance with the stipulations laid down
in JIS R 5201 are shown in Table 1.2-7.
Table 1.2-7. Results of Effluent Tests on Concrete that Uses Rapid-cure Eco-cement
(Aged 28 Days)
Cement
Type
Cd
CN
Pb
Cr6+
T-Hg
Cu
As
Se
B
F
N.D
<0.01
<0.04
<0.0005
<0.02
<0.002
<0.002
<0.05
<0.4
Rapid-c
ure
<0.0
Eco-Ce
05
ment
78
Soil
Environ
ment
0.01
None
0.01
0.05
0.0005
−
0.01
0.01
1.0
0.8
0.01
None
0.05
0.05
0.0005
1
0.01
0.01
1.0
0.8
Standar
ds
Water
Quality
Standar
ds
[Remarks]: “ND” refers to less than maximum detection levels. The inequality symbol refers to
less than maximum amounts. The units used for each value are mg/l.
1.2.1. Cast-in-situ Concrete
This section applies to eco-cement used as cast-in-situ concrete.
[Description]
This section covers the general usage methods and points for consideration in
the use of eco-cement as a substitute for ordinary Portland cement as cast-in-situ
concrete (mainly concrete cement purchased as ready-mixed concrete.)
Eco-concrete must be tested in accordance with the test methods stipulated by JIS R
5201 and JIS R 5202 when it is used as cast-in-situ concrete (ready-mixed concrete),
and the eco-concrete used must satisfy the quality standards stipulated by JIS R
5214.
It is acceptable to use the same environmental safety levels as stipulated for ordinary
Portland cement with eco-cement.
[Description]
Re: 1: The quality standards for eco-cement used as cast-in-situ concrete are
shown in Table 1.2-3. The quality tests for these standards are stipulated by JIS R 5201
and JIS R 5202, and these tests are usually implemented by the manufacturer and then
confirmed by the purchaser with a mill sheet. Quality control at eco-cement factories is
carried out so that the rated values can be guaranteed, and the actual measurement
values must satisfy the rated values by a wide margin, as shown in the table.
The quality of concrete that uses eco-cement must include the following
79
features when compared with concrete that uses ordinary Portland cement.
(1) Required water content is increased slightly in order to attain similar slump
values
1) 2)
.
(2) Viscosity levels are slightly higher.
(3) The slump loss is slightly higher.
(4) The neutrality of the concrete is slightly higher.
(5) The anti-freeze damage capabilities are approximately the same.
As shown in Fig. 1.2.1-2, the relationship between the compression strength
and the cement to water ratio of eco-cement concrete is expressed in a straight line in
the same way as for ordinary Portland cement.
Compaction Strength (N/mm2)
70
Material Age: 91 days
60
50
40
30
20
Ordinary eco-cement
Ordinary eco-cement
10
0
1.4
1.6
1.8
2.0
Cement Water Ratio
2.2
2.4
Fig.1.2.1–2. Example of the Relationship between Compression Strength and Cement to
Water Ratio
The relationship between strength (other than compression strength) and
compression strength is the same as when ordinary Portland cement is used. When
designing eco-cement concrete, it is therefore possible to use the same design mixture
formula as that in the case where ordinary Portland cement is used. Examples of the
results of freeze-thaw tests are shown in Fig. 1.2.1-3.
80
Slump 8cm
100
80
Ordinary Portland cement
60
Ordinary eco-cement
B-type blast-furnace cement
40
0
30
60
90
120
150
180
210
Relative Dynamic Elasticity Coefficient (%)
Relative Dynamic Elasticity Coefficient (%)
120
120
Slump 18cm
100
80
Ordinary eco-cement
60
Ordinary eco-cement
40
0
30
60
1
1
Mass Charge Ratio (%)
Mass Charge Ratio (%)
-2
Ordinary eco-cement
-3
150
180
210
Slump 18cm
Slump 8cm
-1
120
Cycle Count
0
90
0
-1
-2
Ordinary eco-cement
-3
-4
-4
0
30
60
90
120
150
180
0
210
30
60
90
120
150
180
210
Cycle Count
Cycle Count
Fig. 1.2.1-3. Examples of Results of Freeze-Thaw Tests (W/C = 55%)
Re: 2: As already explained in the manufacturing method in 1.2 (2), Chapter 2,
the toxic properties, such as heavy metals, are eradicated during the manufacturing
process, and as the eco-cement is used in the solid state as concrete there is little toxic
effluent, as shown in Table 1.2-6. It can therefore be handled in the same way as
concrete that uses ordinary cement.
(3) Technology Used
1) Design Methods
(1) Ordinary eco-cement is used in plain concrete and reinforced concrete. However, it
cannot be used in reinforced concrete that uses high-strength or high-flow concrete.
(2) Rapid-cure eco-cement can be used only in plain concrete.
(1) The method of handling concrete that uses ordinary eco-cement is the same as for
concrete that uses ordinary Portland cement.
81
(2) When ordinary eco-cement is used in reinforced concrete, the amount of total
chloride ion contained in the concrete during blending must be 0.3 kg/ m3 or less.
(3) Maintaining Records and Repeated Use
If eco-cement is used in concrete structural objects, it is necessary to record this
fact in the construction logs. It is acceptable for concrete that uses eco-cement to
be recycled and reused as concrete aggregate or the like, in the same way as
ordinary cement.
[Description]
Re: 1) Eco-cement contains slightly higher levels of chloride ion in comparison
with ordinary Portland cement and there is little difference in its method of usage.
However, because there are very few results of its use, eco-cement is used in plain
concrete and in reinforced concrete that uses ordinary concrete with only a small
amount of cement.
Examples of uses for ordinary eco-cement are listed in Table 1.2.1-1. Use of
eco-cement in reinforced concrete and pre-stressed concrete, high-strength concrete, and
high-flow concrete that includes large volumes of singular cement must be avoided,
because the amount of chlorine ions in the concrete can become large.
Table 1.2.1-1. Uses for Ordinary Eco-cement
Concrete Type
Structural Object and Product Type
Cast-in-Situ
Reinforced concrete retaining walls, bridge base
structural work, tunnel linings, etc.
L-shaped reinforced concrete guttering for roads,
Reinforced
Concrete
U-shaped covered guttering for roads, assembled
Factory-
earth-retention work, manhole slabs for sewers,
produced
flumes, cable troughs, assembled culverts for road
drainage, L-shaped reinforced concrete retaining
walls, box culverts, etc.
Plain concrete paving, gravity-type retaining walls,
Cast-in-situ
gravity-type abutments, wave-dissipating blocks,
wave-dissipating block fixing blocks, filler concrete,
plain concrete foundations, etc.
Plain Concrete
Boundary blocks for roads, building blocks,
Factory-
interlocking blocks, tension blocks, flat-slab paving,
produced
L-shaped concrete guttering for roads, connecting
blocks, pasteboard blocks, large building blocks, etc.
82
Non-structural Concrete
Leveling concrete, forming concrete, backfill
concrete.
The amount of chloride contained in rapid-cure eco-cement is high at 0.5% or
more of the cement mass, so this material can only be used in plain concrete that is not
reinforced with steel bars. As rapid cure eco-cement displays early strength, eco-cement
is especially suitable for use in plain concrete that can make the best use of this feature.
Re: 2): (1) Fresh concrete that uses ordinary eco-cement has slightly higher
levels of viscosity and a certain amount of additional slump loss in comparison with
concrete that uses ordinary Portland cement, so it is acceptable to handle it in the same
manner.
(2) When the amount of chloride ion in concrete reaches a certain density, it promotes
the corrosion of the steel within the concrete, thereby lowering the durability of the
structure. Taking this into consideration, the total amount of chloride ions that can be
included in concrete is stipulated at 0.30/m3 or less in the Ministry of Land,
Infrastructure, and Transport’s “Standard Performance Specifications for Public Work
Projects” and in the Japan Society of Civil Engineers’ Standard Specifications for
Concrete Structures, and the like.
As chloride ions are added to concrete from the water, cement, aggregate, and
admixture when it is mixed, the total amount of chloride ions included in the concrete
can be calculated from the chloride ion values obtained from the test results for each
material and from the specific design mix formula. The amount of chloride ions included
in ordinary eco-cement exceeds the upper limit of the ratings for Portland cement
regulated in JIS R 5210, but the total amount of chloride ions included in ordinary
concrete does not exceed 0.30 kg/ m3, so it can be used in reinforced concrete. When
calculating the amount of chloride ions included in each material, make sure that the
maximum values of the test results are used.
The method of controlling chloride in reinforced concrete that uses eco-cement
is to conform to the stipulations laid down in the “Standard Performance Specifications
for Public Work Projects”, depending on the method of measurement at construction
sites.
However, the large majority of the chloride ions included in ordinary
eco-cement are fixed in the clinker minerals, and no more than 30% to 40% of the total
content is eluted into the water of fresh concrete in the case of the ordinary eco-cement
available on the open market. The regulated value of chloride in concrete is determined
by the total amount, and when investigations are carried out by measuring the amount
of soluble chloride, 30% or more of the chloride ions contained in the eco-cement are
83
eluted from ordinary eco-cement. It is therefore possible to operate on the safe side by
using 0.7 as the residual ratio (α), and it is concluded that eco-cement can be used as
long as the amount of chloride ions included and calculated by the equation shown
below can be confirmed at 0.30 kg/m3 or less.
A - α x C x D / 100≧B
A: Quality standard value (kg/ m3) of the chloride ions included in concrete
that uses ordinary eco-cement = 0.3 kg/ m3
B: Measured value of chloride ions in fresh concrete (kg/ m3)
α: Residual ratio = 0.7
C: Unit volume of cement (kg/ m3)
D: Amount of chloride ions in ordinary eco-cement (%)
(3) Owing to the effects of chloride, the concretion and hardening times of rapid-cure
eco-cement are swifter than those of ordinary Portland cement, so it is difficult to
transport the former for as long a period of time as ready-mixed concrete. It is therefore
necessary to investigate whether its use in construction is possible without experiencing
problems before using it.
Re: 3): There are few results available for the use of eco-cement. It is therefore
desirable to maintain and store journals on the parts of structural objects where the
eco-cement has been used, for the purpose of investigating future problems and
verifying durability levels.
As shown in 1.2 (3), Chapter 2, eco-cement is used in general concrete, not in
high-strength and high-flow concretes.
It is acceptable to treat concrete using eco-cement in the same way as ordinary
concrete with regard to recycling and reusing the concrete that has already been used.
Factories that produce eco-cement can be found only in limited areas. It is therefore
necessary to implement investigations beforehand as to whether the required amount
of eco-cement satisfying the regulations can be obtained.
[Description]
As of 2002, the only commercially operated factory manufacturing eco-cement was the
one constructed in April 2001 in Ichihara City, Chiba Prefecture. This plant uses
approximately sixty-thousand tons of city waste incineration ash and approximately
thirty-thousand tons of industrial waste, both of which are generated within Chiba
Prefecture, to manufacture approximately one-hundred and eleven-thousand tons of
84
eco-cement every year.
A facility planned to be built in the Hinodecho Futatsu-zuka repository site in Tokyo’s
Nishi-Tama region is scheduled to commence operations in fiscal year 2006. This plant
plans to manufacture one-hundred and sixty-thousand tons of eco-cement from
one-hundred and twenty-five thousand tons of city waste incineration ash every year.
However, the eco-cement produced by these factories will be available only in limited
areas. It is therefore necessary to investigate the possibility of obtaining the required
amount of eco-cement.
Even if the city waste incineration ash and sewage sludge used as the raw
materials for eco-cement clinker contains heavy metals and dioxins in the form of
organic properties, the majority of the lead, copper, cadmium, mercury, and other heavy
metals it contains are separated from the cement clinker in the form of chloride during
the incineration process at temperatures exceeding 1,300 degrees Celsius, and this is
then cooled and collected in the bug filter, together with alkali chloride as dust. Also,
toxic organic matter such as dioxins is dissolved at temperatures that exceed 800
degrees Celsius during the calcination process, so it does not remain as residue in the
exhaust gas, dust, or cement clinker. It can therefore be used in the same way as
ordinary cement.
The cement quality and physiochemical properties are regulated by JIS R 5214
“Eco-cement”, and the characteristics as concrete are regulated by JIS A 5308
“Ready-mixed Concrete” (fiscal year 2003.)
(3) Usage Results
The number of results of using cast-in-situ concrete containing eco-cement
(ready-mixed concrete) is increasing. The JIS A 5308 “Ready-mixed Concrete” standards
were revised in 2003.
Other issues to be considered are as follows.
(4) Repeated Use
Ordinary eco-cement is used in general concrete, not high-strength and
high-flow concrete. Concrete that uses eco-cement can be dismantled and recycled and
reused in the same way as concrete that uses ordinary cement.
Eco-cement is manufactured from city waste incineration ash and other waste
products, taking environmental safety into consideration. Therefore, the cost of
85
production is higher than that of ordinary Portland cement. However, market
prices are determined by supply and demand, and the cost of eco-cement at the
moment is almost the same as that of Portland cement.
(6) Necessity
Eco-cement was developed as a construction material that contributes to the
safe and appropriate processing of city waste incineration ash, which includes toxic
dioxins and heavy metals and is therefore difficult to treat and dispose of, as well as
to the reduction of the burden of garbage disposal and the prevention of
environmental damage.
(7) Carbon Dioxide Emissions
The use of eco-cement does not lead to more carbon dioxide emissions than the
use of ordinary cement. Unlike when city waste incineration ash is used as landfill, a
large amount of carbon dioxide is generated during the process of eco-cement
manufacture, but the amount emitted is approximately the same as when
manufacturing Portland cement, which uses natural resources in its production. There
is therefore no difference in the amount of carbon dioxide emissions when eco-cement is
used as a substitute for Portland cement.
1.2.2. Factory-produced Concrete
This section applies to eco-cement used in factory-produced concrete products.
[Description]
This section applies to eco-cement used in factory-produced concrete products.
Products that use eco-cement are listed in Table 1.2.1-1.
(1) When eco-cement is used in factory-produced products it must be tested in
accordance with the testing methods stipulated in JIS R 5201 and JIS R 5202, and it
must satisfy the quality standards stipulated in JIS R 5214.
(2) The methods of testing the quality of factory-produced products that use
eco-cement are the same as those for ordinary factory-produced products that use
Portland cement.
(3) The total concentration of chloride ions in reinforced concrete products must be
0.30 kg/ m3 or less.
86
The environmental safety standards for factory-produced products that use
eco-cement are the same as those for factory-produced products that use ordinary
Portland cement.
[Description]
Re: 1) Eco-cement that satisfies the stipulations laid down in JIS R 5202 may
be handled in the same way as Portland cement, and therefore may be used for
factory-produced products as long as the eco-cement used meets the stipulations.
The relationship between compression strength and bending strength of
ordinary eco-cement concrete is very similar to that of general concrete. It is also
acceptable to consider the relationship between the Young coefficient and the
compression strength, drying shrinkage, and other dynamic and durability performance
factors as being the same as general concrete. In general, accelerated curing is carried
out with the use of concrete that has a low water to cement ratio, and although the
strength level of such concrete is high at the initial age, the strength increases obtained
through advances in age are not as good as those attained with concrete that uses
ordinary Portland cement manufactured with ordinary curing. As shown in Fig. 1.2.2-1,
ordinary eco-cement concrete has a similar tendency. Consequently, it is possible to refer
to the results of experiments and use the compression strength at the age of 14 days as
the standard for the strength of factory-produced products, most of which are
steam-cured under ordinary pressure. It is therefore acceptable to handle
factory-produced products that use eco-cement in the same way as factory-produced
products that use ordinary Portland cement.
2
圧縮強度（N／mm ）
60
普通エコセメント
普通ポルトランドセメント
普通エコセメント
普通ポルトランドセメント
50
40
30
14日
20
10
0
1.5
試験条件：蒸気養生後に気温20℃,相対湿度60%
の条件で気中養生14日間
蒸気養生条件：前置3時間、昇温20℃/時、最高
温度65℃を3時間保持、以後自然降温）
１日
1.7
1.9
2.1
2.3
2.5
セメント水比
2.7
2.9
3.1
Fig. 1.2.2-1. Relationship between Cement Water Ratio and Compression Strength
Re: 2): As all heavy metals and other toxic substances are removed during the
process of manufacturing eco-cement, and because this cement is used as a solid
material in concrete, there are hardly any problems with the effluent of toxic content
87
that may affect environmental safety, as is shown in Table 1.2-6. It is therefore not
necessary to confirm environmental safety levels during delivery, as long as the
factory-produced product uses eco-cement that conforms to the JIS R 5214 standards.
(3) Technology Used
1) Design Methods
(1) Ordinary eco-cement is used in factory-produced products made from plain
concrete and reinforced concrete.
(2) Rapid-cure eco-cement is used only in plain concrete factory-produced products.
Construction Methods
1) Factory-produced concrete products that use ordinary eco-cement can be handled
in the same way as those that use ordinary Portland cement.
) When ordinary eco-cement is used in reinforced concrete, it must be confirmed
before usage that the concentration of chloride ions in the concrete after mixture is
0.3 kg/ m3 or less.
3) Maintenance of Records and Repeated Use
If eco-cement is used in concrete structural objects, it is necessary to record this fact
in the construction logs. It is acceptable for concrete that uses eco-cement to be
recycled and reused as concrete aggregate or the like, in the same way as ordinary
cement.
[Description]
Re: 1): Eco-cement contains slightly more chloride ion than ordinary Portland
cement (as stipulated in JIS R 5210) but there is little difference between them. As there
are very few data on usage, eco-cement may be used in both plain concrete and reinforced
concrete.
88
Table 1.2.2-1. Categories of Factory-produced Products
Design Category
URC (Plain Concrete)
18
Manufacturing Method Streng
24
URC
Vibration, Pressure Flat concrete slabs
Compaction
Barrier blocks
Shape
Small
30
40↑
RC (Reinforced Concrete)
18
L-shaped guttering
Vibration
Blocks for
Compaction
civil engineering works
30
Interlocking
blocks
RC-2
RC-1
Flat concrete slabs
Barrier blocks
24
PC
(Pre-stressed Concrete)
40↑ 18 24 30 40↑
Fake wood
L-shaped guttering
U-shaped guttering
Concrete
Retaining wal segment
Blocks for
civil engineering works
RC-3
Large-scale products
Box
culverts
PC-1
Cross-ties
Box
culverts
Bridge beams
Large
RC-4
Other Centrifugal
Specialcompaction
Manufacturing
methodsRoll surface
compaction
Hume pipesJacking pipe
piles
PC-2
Pole
piles
The areas of usage are shown in Fig. 1.2.2-2. The areas highlighted in the table
indicate the range of application for eco-cement. The categories of factory-produced
products are divided into URC (plain concrete,) RC-1, RC-2, and RC-3 for reinforced
concrete. Depending on the blend for the factory-produced products categorized under
RC-4, PC-1, and PC-2 (pre-stressed concrete), there will be cases in which the product
contains more chloride ions than the maximum 0.3 kg/m３ allowed for concrete, so the
use of eco-cement should be avoided.
As the concentration of chloride ions contained in rapid-cure eco-cement is
above 0.5% or more of the cement mass, it is recommended that, in the factory
manufacture of products, eco-cement be used only in plain cement that does not include
steel bars.
Re: 2):
89
(1) Fresh concrete that uses ordinary eco-cement has slightly higher levels of viscosity
than concrete that uses ordinary Portland cement, and the amount of slump loss is just
a little larger, which means there is very little difference between them. Therefore, it is
acceptable to handle them in the same manner.
(2) To control the amount of chloride in reinforced concrete that uses eco-cement, the
total amount of chloride included in each of the separate materials used in making it is
calculated. Depending on the method of measuring the chloride content of fresh concrete,
it is possible to use the stipulations laid down in the Ministry of Land, Infrastructure,
and Transport’s “Standard Performance Specifications for Public Work Projects for
Concrete”. However, the large majority of the chloride ions included in ordinary
eco-cement are fixed in the clinker minerals, and no more than 30% to 40% of the total
content is eluted into the water within fresh concrete. As the regulated levels of chloride
in concrete are determined by the total amount, it is safe to confirm the soluble chloride
content by making the measurements in accordance with the methods described in 1.3.1
(3) 2), Chapter 2.
Re: 3): There are few results available for the use of eco-cement. It is therefore
desirable to maintain and store journals on those parts of structural objects in which
eco-cement has been used, in the same way as for cast-in-situ concrete, for the purpose
of investigating future problems and verifying their durability levels.
As shown in 1.2 (3), Chapter 2, eco-cement is used in general concrete, not in
high-strength and high-flow concretes. It is acceptable to treat eco-cement in the same
way as ordinary cement with regard to the recycling and reuse of concrete.
Factories that produce eco-cement can be found only in limited areas. It is therefore
necessary to check whether the required amount of cement satisfying the required
eco-cement regulations can be obtained.
[Description]
As of 2002, the only commercially operated factory manufacturing eco-cement was the
one constructed in April 2001 in Yahata Kaigan-dori, Ichihara City, Chiba Prefecture. In
accordance with Chiba Prefecture’s Eco Town Plan (town planning that creates
harmony with the environment) that aims to achieve zero emissions of waste
throughout the entire prefecture, this plant uses approximately sixty thousand tons of
city waste incineration ash and approximately thirty thousand tons of industrial waste
as raw material to manufacture approximately one hundred and eleven thousand tons
of eco-cement every year. A facility planned for the Hinodecho Futatsu-zuka repository
90
site in the Nishi-Tama region of Tokyo is scheduled to commence operations in fiscal
year 2005. This plant is scheduled to manufacture one hundred and sixty thousand tons
of eco-cement using one hundred and twenty-five thousand tons of city waste
incineration ash every year.
However, the eco-cement produced from these factories is limited to a few areas. It is
therefore necessary to check whether the required amount of eco-cement can be
obtained.
Even if the city waste incineration ash and sewage sludge used as the raw material for
eco-cement clinker contains heavy metals and dioxins in organic form, the majority of
the lead, copper, cadmium, mercury, and other heavy metals it contains are separated
from the cement clinker in the form of chlorides during the incineration process at
temperatures exceeding 1,300 degrees Celsius, and this is then cooled and collected in
the bug filter, together with alkali chloride, as dust. Also, toxic organic materials such
as dioxins are dissolved at temperatures that exceed 800 degrees Celsius during the
calcination process, so they do not remain as residue in the exhaust gas, dust, or cement
clinker. The clinker can therefore be used in the same way as ordinary cement.
The cement quality and physiochemical properties are regulated by JIS R 5214,
“Eco-cement”, and the general rules on the characteristics of concrete products are
regulated by JIS A 5364 “Pre-cast Concrete Products—General Rules on Materials and
Manufacturing Methods” and other related documents.
(3) Usage Results
The number of factory-produced concrete products made from eco-cement is increasing.
In 2002, Chiba Prefecture issued a statement on the “In principal use of eco-cement” in
certain concrete products. JIS A 5364, “Pre-cast Concrete Products—General Rules on
Materials and Manufacturing Methods”, and other related regulations were revised.
(4) Repeated Use
Ordinary eco-cement is used in general concrete, not in high-strength and high-flow
concrete. Concrete that uses eco-cement can be dismantled and recycled and reused in
the same way as concrete that uses ordinary cement.
Eco-cement is manufactured from city waste incineration ash and other waste as raw
91
materials, taking environmental safety into consideration. Although the cost of
production is higher than that of ordinary Portland cement, market prices are
determined by supply and demand, and the price of eco-cement at the moment is almost
the same as that of Portland cement. The cost of producing concrete from eco-cement is
therefore approximately the same as from Portland cement.
(6) Necessity
Eco-cement was developed as a construction material that contributes to the safe and
appropriate processing of city waste incineration ash, which includes toxic dioxins and
heavy metals and is therefore difficult to treat and dispose of, as well as to a reduction
in the burden of garbage disposal and the prevention of environmental damage.
The use of eco-cement does not lead to more carbon dioxide emissions than the
use of ordinary cement. Unlike when city waste incineration ash is used as landfill, a
large amount of carbon dioxide is generated during the process of eco-cement
manufacture, but the amount emitted is approximately the same as when
manufacturing Portland cement, which uses natural resources in its product. There is
therefore no difference in the amount of carbon dioxide emissions when eco-cement is
used as a substitute for Portland cement.
４）
However, if city waste is not used in the
production of eco-cement, then it has to be disposed of using different methods, which
means that its use restricts the amount of carbon dioxide that would be emitted in these
other processing methods.
1) Tsuyoshi Terada, Seiji Meiarashi: Reducing Chloride in Cement that Uses City Waste
Incineration Ash as its Main Component, and the Characteristics of Concrete, Concrete
Engineering, Vol. 37, No. 8, Pages 26 to 30, 1999
2) Public Works Research Institute, Tokyo Metropolitan Public Works Technology
Research Center, Chiba Prefecture, Saitama Prefecture, Aso Cement Co., Ltd.,
Sumitomo Osaka Cement Co., Ltd, Taiheiyo Cement Co, Ltd., Hitachi Cement, Co.,
Ltd.: Report on a Joint Research Project into Development of Reinforced Concrete
Materials that Use City Waste Incineration Ash (Manual), March 2002.
3) Chemical Research Office, Materials and Construction Department, Public Works
Research Institute, Ministry of Construction : Report on the Technology Used for
Energy-saving Cement, Research Results and Technical Manual (tentative title), Public
Works Research Institute Documentation, March 1997
92
4) Susumu Sano, Makihiko Ichikawa, Yuku Tatsuichi, Hideo Shia: Quantification of the
Burden on the Environment Caused by Processing City Waste Incineration Ash,
Resource and Environmental Measures, Vol. 36, No. 10, Pages 58 to 64, 2000
5) Public Works Research Institute: Manual for the Technology Used with Eco-cement,
Published by Gihodo Shuppan, March 2003
93
3. Coal Ash
Overview of Waste
As shown in Table 3-1, the amount of coal ash generated during FY 2001
amounted to approximately 8.8 million t (a 4.5% increase over the previous year), and
there is no doubt that it will continue to follow this trend in the future owing to increased
consumption (amount is expected to exceed 10 million t by 2005). Of the coal ash
generated in FY 2001, 81.4% was used (an 0.8% decrease on the previous year), and the
remaining 18.6% was landfilled.１)
A breakdown of the effective use of coal ash by industrial fields for FY 2001
indicates that cement and concrete used the most, at 74.5% (a 3.9% increase over the
previous year). Coal ash was mostly used as a substitute for clay in the manufacture of
cement, but as the demand for cement has been decreasing in recent years, there is a
limit to the volume that can actually be used in this manner, and the cement
manufacturing industry is gradually drawing closer to its upper limit of consumption.2)
Table 3-1. Transitions in coal ash production and amounts used (unit: 1000 t)
FY 1998
Amount generated
Electricity
FY 1999
FY 2000
FY 2001
5,029
5,757
6,322
6,785
1,760
1,843
2,097
2,025
6,789
7,600
8､429
8,810
5,090
6,133
6,931
7,173
（75.0）
（80.7）
(82.2)
(81.4)
1,699
1,465
1,498
1,636
business
General
industry
Total
Amount used
Breakdown
(%)
Amount
processed in
landfills
Table 3-2. Fields making effective use of coal ash (FY 2001)３）
Field
Detail
Amount used
Use ratio (%)
(unit: 1000 t)
Cement industry
Raw concrete material
74.5%
Concrete mixture
94
4,915
68.5
294
4.1
Mixture for concrete
134
1.9
Public works
Filler for coal mines etc.
320
4.5
industry
Foundation improvement
365
5.1
Subgrade material
104
1.5
Other material for public
62
0.9
12.5%
material
works projects
Construction
Construction boards
309
4.3
industry
Other construction
62
0.9
5.2%
material
Agricultural
Fertilizer and soil
144
2.0
industry 2.0%
improvement materials
Others 5.8%
Others
411
5.7
7,173
100
Total
As there is a limit to the number of uses in the cement field, there is much
expectation for increased usage of coal ash in the field of construction as a measure to
reduce the amount processed in landfill, and much effort is being made to develop the
required technology.
Coal ash is classified into two categories: clinker ash, which falls to the bottom of
boiler furnaces, and fly ash, which is accumulated in dust collectors. Fly ash is known as
raw powder before grading, and then as fine powder or coarse powder after grading. The
basic materials of fly ash as stipulated by JIS are the fine powder and coarse powder. Fly
ash that satisfies JIS standards has many different uses, including in concrete. The coal
ash covered in this manual includes the raw powder of clinker ash and fly ash and the fly
ash that does not satisfy JIS standards.
The standardization of coal ash is advancing rapidly overseas, and the ash is
used in vast quantities for road materials. Revisions to the Manual for Design and
Construction of Asphalt Pavement in Japan have made it possible to use fly ash as
asphalt filler and clinker ash as sub-base course material, subgrade material, anti-frost
material, and filter layer material since 1988. Expectations are also high for its use as
subgrade material in the cement stabilization process. Construction tests on measures for
strengthening soft foundations and verification tests on high embankments also show
95
that it is effective as embankment fill. In the role of filler it has also been used as tunnel
backfill and in temporary underwater structures. Moreover , foundation solidification
construction methods have been developed by mixing coal ash with additives and rolling
it to make surface protection layers for weak foundations, as used in storage sites or the
like4).
Trace components that have been absorbed by timber are condensed in coal, and
there are cases where hexavalent chromium, arsenic, and other heavy metals have been
detected in quantities that exceed environmental standards. Boron, which was newly
added to the Soil Environmental Standards in 2001, has also been detected in quantities
that exceed environmental standards. It is therefore important to implement tests related
to environmental safety before actual use. The cement solidification process and other
processes explained in this manual are effective as detoxification methods.
[Reference]
1) Center of Coal Utilization of Japan: Report on Surveys of the Current Situation
Relating to Nationwide Use of Coal Ash (Fiscal 1999), March 2001
2) The Cement Shimbun Co., Ltd.: The Cement Shimbun, February 4th 2002
3) Japan Coal Energy Center: Breakdown of the Effective Usage of Coal Ash in Fiscal
2001, http://www.jcoal.or.jp/coaltech/coalash/ash02.html
4) Environmental Technology Association, Japan Fly Ash Association: Coal Ash
Handbook 2000 Edition, March 2001
3.1. Cement Admixture Solidification
Measures for detoxifying coal ash to be used as soil, but that does not satisfy
environmental safety standards, include heat processing, such as the solubilization and
solidification process, and chemical processing, such as solidifying it into a cement
mixture and performing chemical treatment. The cement admixture solidification
process is a method of solidifying coal ash by mixing it with a certain percentage of
cement, gypsum, blast-furnace slag particles, and water. There are two methods of
manufacturing the solidification processed material depending on the type of
construction. One is crushing the solidified material and then sorting it into
predetermined particle sizes. The other is granulating the material with a
predetermined size immediately after additives have been added and then curing it for
solidification. It is necessary to wait for the results of future inspections to discover the
effects of the cement admixture solidification process on environmental safety in the
96
long term. However, there are many different kinds of cement-stabilized coal ash
products for use as construction materials that satisfy environmental standards
through the selection of fuel coal types and adjustment of the amount of cement for
admixture solidification already being developed, and some of them have acquired the
Construction Technology Inspection Certification.
3.1.1. Embankment Fill and Artificial Foundation Materials
This section applies to the use of coal ash that has been subject to cement admixture
solidification as embankment and artificial foundation material.
[Description]
This section applies to the use of coal ash that has been manufactured as cement
admixture solidification coal ash, as road embankment, structural embankment super
levees, landfill, basic foundations, and backfill for structural objects.
Quality standards exist for the material and for construction management for each
separate construction type with regards to embankment and artificial foundation
material, and each of the relevant quality standards must be satisfied.
Coal ash that he been crushed from solid cement must satisfy the following
environmental safety standards.
(1) Environmental Safety Standards
The amount of toxic eluents must satisfy 26 of the 27 maximum effluent limits (hereinafter
known as the effluent standards), with the exception of copper, listed in Report 46 issued by
the Ministry of the Environment on August 23rd 1991 in the Environmental Quality
Standards for Soil Pollution (see Table 1 in the Appendix.)
The amount of toxic content must satisfy the maximum toxic content limits for nine
substances listed in Section 2, Article 18, in the Environmental Quality Standards for Soil
Pollution (see Table 2 in the Appendix)
(2) Test Methods
The effluent tests are to be carried out in accordance with the stipulations laid down in
Ministerial Announcement No. 46 issued by the Ministry of Environment on August 23rd
97
1991 in the Environmental Quality Standards for Soil Pollution (see table in Appendix 1.)
The toxic content tests are to be carried out in accordance with the stipulations laid
down in Measurement Methods for Surveys into Toxic Content in Soil, Ministerial
Announcement No. 19 issued by the Ministry of Environment on March 6th, 1991 (see
table in Appendix 1).
When cement admixture solidification material is to be used, it must have had effluent
tests carried out on each lot, and the results of these tests must be displayed on the
quality display card attached to it.
[Description]
Re: 1): The quality standards of cement solidification coal ash used as
embankment, levee and backfill material must conform to the “Construction Sludge
Recycling Policies”1) as shown in Table 3.1.1-1.
Table 3.1.1-1. Required quality levels of embankments and levees
Material Rating
Usage
Road
Public works Road
River levees
Structura
(subgrade)
structural
embankme High-standar General
l backfill
foundations backfill
nts
d levees
levees
Maximu
m
50 mm or
particle
less
size
―
(100 mm or
less)
―
100 mm or
less
(150 mm or
less)
―
Particle
Fc≦25%
size
―
（Fc≦25%）
―
40% or less of
φ37.5 mm
mixed in
Fc>１5%
―
Consiste
ncy
―
(PI≦10)
―
―
―
―
―
―
qc
≧400 kN/m2
―
―
―
―
Dc≧90%
Dc≧80%
―
―
(Above
Strength CBR
rating)
Construction management rating
Sea
reclam
ation
(Above CBR
rating)
Within a
range where
a moisture
Superviso
level of the
Moisture r
maximum
Content instructio
moisture
ns
content and
Dc90% can
be obtained
Within a
range
where a
moisture More moist
level of the than the
maximum maximum
moisture moisture
content
content
and Dc90%
can be
obtained
―
Dc≧90%
Dc≧90%
―
―
―
―
Dc≧90%
Dc≧90%
Dc≧85%
Compacti
on level
Viscous
soil
Va≦10%
Sr≧85%
98
Viscous soil
Va=2-10%
Sr=85-95%
Sandy soil
Viscous soil
Va=2-10%
Sr=85%–95%
Sandy soil
―
Sandy soil Va≦15%
Va≦15%
30 cm (20
Top layer cm or less
30 cm or
20 cm or less 20 cm or less
thickness for the
less
subgrade)
Others
―
―
―
―
Developm
ent of
technolog
y for
recycling
Road
Road
Standards, waste for
Construction Construction
etc.
the entire
Guidelines Guidelines
profession
al
constructi
on
industry
Va≦15%
―
―
―
qc≧400
kN/m2
―
―
High-Standa
rd Levee
Road
Construction River
Constructi
Investigation Construction
on
Committee Manual
Guidelines
documentatio
n
―
Legend: Fc: ratio of fine powder included; PI: plasticity index; qc: cone index; Dc: average
compaction level; va: Air void; Sr: saturation level; --: not rated; ( ): desired values
The test methods for road embankments, road backing, and backfill are to be
implemented in accordance with the stipulations laid down in “Road Construction
Guidelines” (Japan Road Association) and the “Construction Management
Requirement Standards” (Japan Highway Public Corporation). Tests on general levees
are to be carried out in accordance with the “River Construction Manual” (Japan
Institute of Construction Engineering).
Examples of the performance standards for embankment material that uses coal
ash manufactured with the cement solidification crushing method are shown in
Table 3.1.1-2.
Table 3.1.1-2. Examples of performance standards for embankment material manufactured
with the solidification crushing method2)
r
m
Raw material
Cat.
Standard mixture
(dry quality ratio)
100
Item
Coal ash
Details
Fly ash (JIS A 6201 II to IV types)
Cement
Blast-furnace cement B-type (JIS R 5211)
or ordinary Portland cement (JIS R 5210)
4–8
Additives
Gypsum
Blast-furnace slag particles (JIS A 6206)
0–10
Shearing resistance
25 degrees
angle
99
Adhesive power
30 kN/m2 or more
CBR
10% or more
Expansion ratio
1％ or less (good condition)
Long-term strength Long-term strength must not be exorbitant
Cone penetration
1200 kN/m2 or more
resistance
Moisture density
1.0–1.6 kg/cm3 (dry density 0.9–1.2 g/cm3)
Stone-mixed soil material Sm-R (particle size can be adjusted in
Particle size
accordance with usage)
Permeability
Low permeability within the same range as powdered sand
coefficient
Elution of toxic
Below the environmental standards for soil
substances
Re: 2) Abridged versions of the laws that regulate environmental safety
standards and test methods are provided in Appendixes 1 and 2. Appendix 4 provides a
compilation of the maximum permissible values for effluent and content values of toxic
substances as the environmental risk evaluation standards. In other words, when
evaluation standards for the Environmental Quality Standards for Soil Pollution and
the Enforcement Regulations of the Soil
Contamination
Countermeasures Law are
compiled together, they look like the details shown in Table 3.1.1-3 on the following page,
and all effluent and content values of toxic substances obtained through tests must
satisfy these evaluation standards accordingly.
100
Table 3.1.1-3. Evaluation standards for evaluating environmental risk
Item
(Effluent standards)
(Toxic content standards)
Cadmium and its compounds
0.01 mg/L or less
150 mg/kg or less
Hexavalent chromium
0.05 mg/L or less
250 mg/kg or less
compounds
Simazine
0.003 mg/L or less
Cyanide compounds
None must be detected
Thiobencarb
0.02 mg/L or less
Carbon tetrachloride
0.002 mg/L or less
1,2-dichloroethane
0.004 mg/L or less
1,1-dichloroethylene
0.02 mg/L or less
cis-1,2-dichloroethylene
0.04 mg/L or less
1,3-dichloropropane
0.002 mg/L or less
Dichloromethane
0.02 mg/L or less
Mercury and its compounds
0.0005 mg/L or less
15 mg/kg or less
Selenium and its compounds
0.01 mg/L or less
150 mg/kg or less
Tetrachloroethylene
0.01 mg/L or less
Thiram
0.006 mg/L or less
1,1,1-trichloroethane
1 mg/L or less
0.006 mg/L or less
Trichloroethylene
0.03 mg/L or less
Lead and its compounds
0.01 mg/L or less
150 mg/kg or less
Arsenic and its compounds
0.01 mg/L or less
150 mg/kg or less
Fluorine and its compounds
0.8 mg/L or less
4000 mg/kg or less
Benzene
0.01 mg/L or less
Boron and its compounds
1 mg/L or less
Polychlorinated biphenyls
50 mg/kg or less (free cyanide)
4000 mg/kg or less
(PCBs)
Organic phosphorous
compounds
Alkyl mercury
For safety management purposes, the purchaser must submit a quality display
card that lists all of the predetermined items as shown in Table 3.1.1-4 to the
manufacturer of recycled materials.
101
Table 3.1.1-4. Items required in safety quality displays
No.
Required item
(1)
Name and type of materials
(2)
Name of manufacturer
(3)
Name of manufacturing plant
(4)
Date of manufacture or date of shipping
(5)
Lot number
(6)
Quantity
(7)
Quality assurance display (indicates the quality
assurance levels for the items listed in Table
3.1.1-3, such as cadmium, 0.01 mg/l or less; lead,
0.01 mg/l or less, etc.
(8)
Miscellaneous (particle size, physical
characteristics, results of effluent tests, etc.)
Safety inspections are to be carried out at the time of shipping by the
manufacturer and at the time of delivery by the recipient. The inspection at the time of
delivery is to be implemented in accordance with the test results created by the
manufacturer. Sample testing must also be carried out if deemed necessary and if doubts
regarding safety arise. The method of extracting samples for the sample tests are to
conform to the stipulations laid down in JIS Z 9015, “Procedures for Discreet Value
Sample Inspections”.
(3) Technology Used
1) Design Methods
All of the factors relating to crushed coal ash cement admixture solids, such as maximum
particle diameter, particle size, and consistency, as well as the strength, moisture
content, compaction level, and top layer thickness of the embankment and soil structures
in which it is used, must conform to the relevant construction standards.
(1) It must be confirmed that a sufficient amount of stable cement admixture solids can
be obtained without fail.
(2) When cement admixture solids are to be used in locations where they come into
102
contact with acidic water, it is necessary to consult with the manufacturer beforehand to
guarantee safety, even if it requires change of conditions of the effluent tests.
(3) All construction methods must conform to ordinary construction procedures.
3) Maintaining Logs and Repeated Use
When using coal ash cement admixture solids for the construction of embankments and
artificial foundations, the purchaser must store all design plans, including plan views,
cross-sectional diagrams and quantity tables, and the like, together with all recycled
material test results and construction diagrams.
If the conditions laid out in the standards stipulated by this section are satisfied, the coal
ash cement admixture solids used in embankments and artificial foundations can be
drilled and reused as embankment and foundation material.
[Description]
Re: 1) and 2): The design of road foundations, road backing, and backfill that
uses coal ash admixture solids must conform to the methods and procedures stipulated in
the “Road Construction Guidelines” and the “Construction Management Requirement
Standards” issued by the Japan Highway Public Corporation. The methods and
procedures for the design and construction of general levees must conform to the
stipulations laid down in the “River Construction Manual” issued by the River
Development Technology Association. The methods and procedures for the design of
structures in residential areas must conform to the stipulations laid down in the “Public
Works Construction Standards” issued by the City Foundation Maintenance Co., Ltd.
The contractor in charge of construction must submit construction diagrams, a
delivery acceptance form on the coal ash cement admixture solids, the results of tests, and
all other relevant documentation.
Re: 3): When using coal ash cement admixture solids for the construction of
embankments and artificial foundations, the purchaser must store all design plans,
including plan views, cross-sectional diagrams and quantity tables, all test results on the
coal ash cement admixture solids, and other construction diagrams, and store them
together for the purpose of reusing the relevant subgrade materials repeatedly or disposal
of the relevant materials.
When coal ash cement admixture solids used in embankments and artificial
foundations are drilled and reused as embankment and foundation material, the
103
purchaser must confirm the details of all design documentation created when they was
used previously, and consult with the manufacturer of the cement admixture solid coal
ash to establish appropriate methods and procedures for its reuse.
The content and the amount of heavy metals extracted from coal ash differ depending
on the configuration of the thermal power plant in which the coal ash was produced and
on the raw materials from which it was made. There are also differences between
manufacturing lots.
The effects of slaking (the process in which particle size is reduced by the repeated
moistening and drying of mudstone and other rocks with high levels of moisture
absorption and as a result promoting disintegration) caused by the repeated crushing,
drying, and moistening that occur during heavy surface compaction is thought to cause
problems with cement admixture coal ash.
2) Usage Results
With the exception of the products that have been subject to construction technology
inspections and awarded certificates, there are very few examples of usage.
3) Supply
Although there are economic advantages in locating plants capable of manufacturing
coal ash cement admixture solids in areas where coal ash is produced, coal ash is
produced in a limited number of prefectures that have thermal power plants. There
are also many manufacturing plants that are currently in the testing stage, so
currently there is very little product available for supply in large quantities.
Although no carbon dioxide is emitted during the manufacture of coal ash cement
admixture solids, carbon dioxide is emitted indirectly through the use of cement.
[Description]
Re: 1) Cement solidification coal ash differs in accordance with the method in
which the raw coal ash and solid matter are manufactured, so it is necessary to carry out
thorough quality inspections before using cement solidification admixture coal ash. It is
104
recommended that cement solidification admixture coal ash manufactured by plants that
have been confirmed by public organizations to satisfy the stipulated performance levels
be used for embankments, artificial foundation material, or the like.
In addition to guaranteeing strength levels, including anti-slaking and anti-crushing
characteristics that correspond with the objective of usage, it is also necessary to make
sure that slaking and crushing during storage, transportation, and construction do not
have any adverse effects on the construction of earth structures.
Re: 2) and 3): There are many results available for products that have acquired
construction technology inspection certification. It is recommended that these results be
referred to when using coal ash for the first time, and full implementation of all relevant
quality tests and test constructions are recommended. It is also necessary to implement
investigations into the possibility of supply and transportation costs before use.
Re: 4) Although no carbon dioxide is emitted during the manufacture of coal ash
cement admixture solids, it is emitted indirectly through the use of cement. The amount
of cement that can be used is approximately 5% or less of the amount of solubilized and
solidified coal ash.
[Reference]
1) Advanced Construction Technology Center: Construction Sludge Recycling Guidelines,
January 1999
2) Okinawa Electric Power Co., Inc.: Report on Public Works Material Technology and
Technology Inspection Certification (Technology Inspection Certification, Edition 1220,
“Crushed Hard Soil Material”, Artificial Foundation Material that Uses Coal Ash, Public
Works Research Center, 2000
3.1.2. Subgrade Materials
This section applies to the use of cement admixture solidification coal ash as the sub-base
course material for simple paving, asphalt paving, and cement concrete paving.
[Description]
If the subgrade material that is made by solid cement is crushed and mixed with
cement, it can be used for construction using the same methods that are used for ordinary
sub-base course material. Also, if the cement stabilization process standards are satisfied,
105
the same level of particulate materials as the subgrade made with ordinary materials by
use of stabilization can be produced. This section applies to the case where coal ash made
by crushing solid cement is used as subgrade material.
The quality standards of cement solidification coal ash that is used as sub-base
course material must conform to the stability-processed concrete sub-base course
stipulated in the “Guidelines for Pavement Design and Construction” and the “Manual
for Design and Construction of Asphalt Pavement”.
The environmental safety standards and test methods for solid cement coal ash must
conform to the stipulations laid down in Section 2, 3.1.1 (2) 2). In other words,
environmental safety must be confirmed by carrying out the effluent tests on 26
substances and the toxic content tests on nine substances.
[Description]
Re: 1): The quality standards of solid cement coal ash that is used as sub-base
course material must conform to the stability-processed concrete sub-base course
stipulated in the “Guidelines for Pavement Design and Construction” and the “Manual
for Design and Construction of Asphalt Pavement”. An outline of the quality standards
related to the physical properties of sub-base course material are shown in Table
1.1.1-4.
Re: 2): Conforms to the description provided in 3.1.1. (2) 2), Chapter 2.
The cost of cement solidification processing is lower than that processing
molten slag, and the physical properties and environmental safety levels decline if only
small amounts of solid cement are used.
An example of the permeability sampling device used in testing the effluents in
sub-base course material made from crushed solid cement is shown in Fig. 3.1.2-1.
Ion-exchanged water (740 ml per day) is scattered onto the material twice a week,
based on average precipitation data, and eluted samples are then taken from the
bottom. Examples of elution test results are shown in Table 3.1.2-1.
106
Gravel layer
Subgrade material
Filter
Gravel layer
Fig. 3.1.2-1. Permeability sampling device
107
Table 3.1.2-1. Test results of permeability elution on sub-base course material made
from crushed solid cement
Measured items
Results (mg/l)
1 week 2 weeks 3 months
Contamination
6
Environmental standards
regarding aquatic contamination
Alkyl mercury compound
Mercury and its compounds
none
"
none
none
none Must not be detected
"
"
"
0.0005 or less
Cadmium and its compounds
"
"
"
"
0.01 or less
"
"
"
"
0.01 or less
Hexavalent chromium
0.02
"
"
0.01
0.05 or less
Arsenic and its compounds
none
"
"
none 0.01 or less
Cyanogen compounds
"
"
"
"
Must not be detected
PCB
―
―
―
"
Trichloroethylene
―
―
―
"
0.03 or less
Tetrachloroethylene
―
―
―
"
0.01 or less
Dichloromethane
―
―
―
"
0.02 or less
―
―
―
"
0.002 or less
1,2-dichloromethane
―
―
―
"
0.004 or less
1,1-dichloromethane
―
―
―
"
0.02 or less
cis-1,2-dichloromethane
―
―
―
"
0.04 or less
―
―
―
"
1 or less
―
―
―
"
0.006 or less
1,3-dichloropropene
―
―
―
"
0.002 or less
Benzene
―
―
―
"
0.01 or less
Thiram
―
―
―
"
0.006 or less
Simazine
―
―
―
"
0.003 or less
Thiobencarb
―
―
―
"
0.02 or less
"
Selenium and its compounds
―
―
―
0.01 or less
（3）Technology Used
1）Design
Structural designs for paving that uses subgrade material made from crushed solid
cement must conform to the methods and procedures stipulated in the “Guidelines for
Pavement Design and Construction” and the “Manual for Design and Construction of
108
Asphalt Pavement”, and designs are to be decided in consideration of the road-bed
conditions, the amount of traffic, the conditions and economic viability, etc.
2）Construction
The construction of sub-base course that uses subgrade material made from crushed
solid cement must conform to the construction methods stipulated in the
“Guidelines for Pavement Design and Construction” and the “Manual for Design
and Construction of Asphalt Pavement”.
3）Maintaining Logs
Test results and construction journals must be stored for further reference when using
solidified coal ash products as subgrade material.
[Description]
Re: 1): The design values of material used as sub-base course material are to be
set at 0.98 MPa for unconfined compression strength, (aｎ ) 0.25 for the equivalence
conversion index, and 15 cm for the minimum thickness of the subgrade.
Re: 2): It is necessary to be careful when stacking, transporting and unloading
subgrade material to ensure that mud or toxic materials are not mixed in with it, and
that the material does not split. Temporary storage of the material at the construction
site must be limited to a minimum volume, and the material is not to be accumulated.
When the subgrade material dries out, an appropriate amount of water is to be sprinkled
on it with the use of a tire roller or the like. To prevent the material from adhering to the
roller, surface compaction is to be carried out after the condition of the road surface is
verified, and the surface compaction is to be continued until the predetermined levels of
compaction have been attained. All horizontal joints of the finished surface are vertically
cut off deposit new subgrade material therefrom.
Vertical joints are to be located in a framework that is as thick as the finished
article and are to be removed once the surface compaction process has been completed. As
there is a tendency for cracks to appear in joints where new subgrade material is to be
deposited after a certain period of time, it is recommended that the joint gaps be filled as
quickly as possible.
Conforms to 3-1-1 (4), Chapter 2.
[Description]
109
Conforms to the description provided in 3.1.1 (4), Chapter 2.
[Reference]
1) Chubu Electric Power Company: Report on the Construction Technology Inspections
and Certification for the “Ash Roban” Subgrade Material that uses Coal Ash, Public
Works Research Center
2) Japan Society of Waste Management Experts: Waste Handbook, page 997, 1997
110
3.2. Lime Admixture Solidification
Coal ash reacts with desulfurized sludge or the calcium contained in caustic
lime and hardens. Lime admixture solidification material is the name of powder or
particulate matter made from coal ash and flue gas desulfurization sludge (gypsum or
gypsum plus sulfurous gypsum) to which a small amount of lime has been added in
accordance with requirements and then moisture-adjusted.
This section applies to the case where lime admixture solidification material is used as
sub-base course, road-bed material, or embankment fill for filled ground after being
compacted.
[Description]
Coal ash can be used as sub-base course material, road-bed material, and
embankment fill for public works projects if it is reacted with flue gas desulfurization
sludge and caustic lime, which causes it to harden, and then surface-compacted.
It must have the strength to withstand pile-driving and earth excavation, and
the unconfined compression strength must be 10 kPa or lower when used as general
embankment material, but there are no such restrictions on its use as sub-base course
material and road-bed material.
The quality standards when coal ash is used as sub-base course material must conform
to the lime stabilized substratum subgrade stipulations laid out in the Guidelines for
Pavement Design and Construction and the Manual for Design and Construction of
Asphalt Pavement.
The environmental safety standards must conform to the stipulations laid down in
3.1.2 (2) 2), Chapter 2. In other words, environmental safety must be confirmed by
carrying out effluent tests on 26 substances and toxic content tests on nine substances.
[Description]
Re: 1): The quality standards of the coal ash used as sub-base course material
111
must conform to the regulation on lime-stabilized sub-base course laid down in the
“Guidelines for Pavement Design and Construction” and the “Manual for Design and
Construction of Asphalt Pavement”. Refer to Table 1.1.1-4, Chapter 2 for an outline of the
quality standards.
Examples of the quality standards for admixture solidification material that
have acquired construction technology inspection certification are shown in Table 3.2.1-1.
The quality standards for coal ash used as sub-base course material must conform to the
regulation on lime-stabilized sub-base course laid down in the “Guidelines for Pavement
Design and Construction” and the “Manual for Design and Construction of Asphalt
Pavement”, and the standards for road-bed material are based on the replacement
materials in the “Manual for Design and Construction of Asphalt Pavement”.
Table 3.2.1-1. Quality standards for lime admixture solidification material1)
Location used
Quality standards
Sub-base course
Unconfined compression strength [10 days]
0.7 N/mm2 or more
REVISED CBR [10 days] 30% or more
Road-bed
Unconfined compression strength [10 days]
0.2 N/mm2 or more
REVISED CBR [10 days] 20% or more
Re: 2): Refer to the description provided in 3.1.2 (2) 2), Chapter 2.
(3) Technology Used
1) Design
The equivalence conversion index when coal ash is used as sub-base course material is to be
set at 0.25. The CBR value is 20% when it is used as replacement material for road-bed
material.
2) Construction
The construction method for coal ash solidified with lime admixture is the same as the
method used for earth and sand.
3) Maintaining Journals
The fact that coal ash solidified with lime admixture has been used in sub-base course and
road-beds must be included in the test results of construction journals.
112
[Description]
Re: 2): Ordinary construction equipment can be used for transporting, shaping,
forming, and rolling coal ash solidified with lime admixture. The moisture content must be
close to the optimum moistness ratio when the coal ash is delivered to the site. If it is left
untreated for a long time after delivery, it will dry out quickly, especially in summer, the
advancement of compaction density deterioration will reduce its strength, and the pozzolonic
reaction may occur. So, rolling must be carried out as soon after delivery as possible. When
the surface is dried, it is necessary to sprinkle water to keep the moistness near the
optimum value and roll the surface. The standard thickness for each finished layer is 20 cm
or less for both sub-base course and road-beds; approximately 1.2 times the thickness of the
finished layer can be used as lift.
The raw material consists of many fine particles, possibly increasing the
moisture content in the rain to the same consistency as mud, and making surface
compaction very difficult. Therefore, construction should not be carried out in the rain
as a basic principle. If it begins to rain unexpectedly during construction, cover the lime
admixture solid that has not been rolled, and make sure it is not moistened by the rain.
Lime admixture solid that has been recently rolled is weakened by heavy rain even
after surface compaction. In such a case, it is possible to use ordinary equipment when
resuming construction, leaving the material under fine weather one or two days after
the weather has improved before resuming work.
It is not possible to store coal ash that has been solidified with lime admixture for a long
period of time after it has been manufactured, so it is necessary to use it as quickly as
possible after delivery.
2) Supply
It is necessary to implement investigations to ascertain that the required amounts of
coal ash solidified with lime admixture can be obtained before use.
3) Repeated Use
It is necessary to implement the solidification process again when it is to be reused.
[Description]
113
Environmental safety tests must be implemented on coal ash solidified with lime
admixture to confirm that the prescribed standards are satisfied.
RE 1):
If coal ash solidified with lime admixture is left untreated for a long period of time after
delivery, it will dry out quickly, especially in summer, resulting in reduced strength owing to
the deterioration of compaction density and the pozzolonic reaction.
RE 2):
It is recommended that coal ash solid with lime admixture be used near the producing
factory so as to reduce transportation costs.
RE 3):
It is thought to be possible to reuse coal ash solid with lime admixture either as subgrade
material when it resolidified; or when its strength is great, it can be crushed, similar to
the cement admixture solid crushing, to be used as granules.
Environmental safety tests must be implemented on coal ash solidified with lime
admixture to confirm that the prescribed standards are satisfied.
(2) Usage Results (1999 to 2002)
- Road maintenance work on the Tsuruga Line, Kinki Expressway, sub-base course
material (Fukui Prefecture) 582 m2, thickness 15 cm, 146 t.
- Pavement replacement work, road-bed improvement material (Fukuoka Prefecture) 420
m2.
- Embankment material (Okinawa Prefecture) 200 m2.
- Power plant work, road foundations (public sector) 2600 m2, thickness 10 cm, 360 t.
Prices differ depending on the amount required and the location that it is to be used, so it
is necessary to investigate market prices.
(4) Necessity
Approximately 19% of coal ash was processed in landfill sites in FY 2000, but
expectations are high for the development of technology that will enable it to be used in
114
large quantities in public works projects.
No carbon dioxide is emitted when coal ash lime admixture solidification material is
used as subgrade material. However, carbon dioxide is emitted in the manufacture of
cement and electrical power.
[Reference]
1) Mitsui Construction Co., Ltd.: Subgrade, Road-Bed and Embankment Material “Pozotec”
that Uses Coal Ash, Technological Inspection Certification Report on Construction
Technology Developed in the Public Sector, Edition 0609, Public Works Research Center,
March 1995
3.3. Sintering and Calcination Processes
Calcinated fly ash is solid matter solidified by firing at high temperatures in
rotary kilns or other furnaces after the coal ash has been processed into granules.
Calcinated fly ash is hard and has a low density, and therefore is capable of being used
as concrete aggregate.
3.3.1. Artificial Aggregate
This section applies to the use of artificial fly ash aggregate in plain, reinforced,
and pre-stressed concrete structural objects.
[Description]
Artificial fly ash aggregate is a dense, non-foamed aggregate produced by
adding property adjustment materials (calcium carbonate powder or the like) and
adhesive materials (bentonite or the like) as sub-agents to the fly ash that forms its
main ingredient, and then processing it into granules and sintering it. An outline of the
manufacture of artificial fly ash aggregate is shown in Fig. 3.3.1-1.
Two types of coarse aggregate are manufactured for use as concrete aggregate:
one with a maximum size of 20 mm and the other with a maximum size of 15 mm. This
section applies to the use of this material in plain, reinforced, and pre-stressed concrete
structural objects.
115
Fly ash
Sub-agents
Cooler
Rotary Kiln
Blender
Water
Moisture adjustor
Granulator
Sieve
End product
Fig. 3.3.1-1. Outline of the Manufacture of Artificial Fly Ash Aggregate1)
To make sure that artificial fly ash aggregate has the same moisture absorption rates
and strength as ordinary aggregate, it must satisfy the stipulations laid down in the
“Quality Standards for High-Strength Artificial Fly Ash Aggregate for Use in Concrete
(proposed)” issued by the Japan Society of Civil Engineers.
The environmental safety standards and test methods for artificial fly ash aggregate
must conform to the stipulations laid down in Section Two, 1.1.1 (2) 2).
[Description]
Re: 1): The quality standards for the Japan Society of Civil Engineers’ JSCE-C
101 “Quality Standards for High-Strength Artificial Fly Ash Aggregate for Use in
Concrete” are shown in Tables 3.3.1-1 to 3.3.1-3.
Table 3.3.1-1. Chemical Properties and Chemical Characteristics
Quality item
Ignition loss
Calcium oxide (as CaO)
Sulfur trioxide (as SO3)
Chloride (as NaCl)
%
%
%
%
Regulated value
1.0 or less
30 or less
0.5 or less
0.01 or less
Table 3.3.1-2. Physical characteristics
Quality item
Regulated value
116
Crushing load
φ 5–10 mm
φ10–15 mm
φ15–20 mm
Absolute dry density
Moisture absorption rates (24 hrs)
Stability
Abrasion loss (percentage of
aggregate loss)
Fine particle content
kN
0.70 or more
kN
kN
g/cm3
%
%
%
1.50 or more
2.10 or more
2.0 or less
3.0 or less
5 or less
30 or less
%
1.0 or less
Table 3.3.1-3. Particle size
Note #1: The nominal dimensions of the sieves conform to the JIS Z 8801-1 standards
for metal sieves at 37.5, 26.5, 19, 16, 9.5, 4.75, and 2.36 mm.
Category of
by range of
aggregate
particle size
2005
Percentage (%) of material that passes through sieves
40
25
Nominal size of sieve holes (mm)#1)
20
15
10
−
100
90–100
−
1505
−
−
100
90–100
5
2.5
20–55
0–10
−
40–70
0–15
−
Re: 2): Artificial fly ash aggregate is a solid that has been heat-hardened in
furnaces at temperatures of between 1050 and 1200 °C. The environmental safety
standards and test methods must consequently conform to the stipulations laid down in
Section Two, 1.1.1 (2) 2). An example of the effluent tests results acquired from artificial
fly ash aggregate up until now is shown in Table 3.3.1-4.
117
Table 3.3.1-4. Effluent test results for artificial fly ash aggregate1)
Cadmium
Lead
Arsenic
Hexavalent
chromium
Total mercury
Total cyanide
Measured value
maximum volume less than
0.001 mg/l
0.005 mg/l
0.005 mg/l
0.02 mg/l
0.0005 mg/l
0.1 mg/l
Evaluation standard
0.01 mg/l or less
0.01 mg/l or less
0.01 mg/l or less
0.05 mg/l or less
0.0005 mg/l or less
none to be detected
(1) Technology Used
1) Design
Design mix formula for concrete that uses artificial fly ash aggregate must be
implemented while taking into account the fact that the density of the aggregate is
smaller than that of ordinary aggregate.
The design of concrete structural objects that use artificial fly ash aggregate must
also be implemented while taking into account the fact that the density of the aggregate
is smaller than that of ordinary aggregate.
When concrete that uses fly ash is to be poured with the use of a pressure pump, it is
necessary to confirm the effectiveness of the pressure pump beforehand.
When artificial fly ash aggregate is used in structures, it is necessary to mention this fact
in the design mixture formula.
As it is not possible to extract only the artificial fly ash aggregate from concrete, it is
extremely difficult to reuse it.
[Description]
Re: 1): The strength of concrete that uses artificial fly ash aggregate is similar
to that of concrete using ordinary aggregate, while reducing unit weight by around 10%.
That is because the aggregate used has similar strength to that of ordinary aggregate
but has a lighter absolute dry density of around 1.8 g/cm3. Also, the aggregate is more
spherical in configuration, which improves the fluidity of fresh concrete, thus enabling
reductions in the amount of water content required to maintain the required levels of
118
fluidity and to reduce dry compaction levels. Furthermore, it has similar levels of
moisture absorption as ordinary aggregate at 3.0% or lower, and this provides it with
excellent freeze-damage resistance that cannot be obtained with concrete that uses
conventional, artificial, lightweight aggregate containing expansion clay. The Young
coefficient is slightly smaller than the one for concrete that uses ordinary aggregate.
The endurance inspections for concrete structures must conform to the [Construction]
section in the “Standard Specifications for Concrete Structures” (Japan Society of Civil
Engineers). In accordance with the details laid down in 1) of the Reference, the
compaction strength and endurance levels of concrete that uses artificial fly ash
aggregate is almost the same as concrete that uses ordinary aggregate.
The design of concrete structures that use artificial flay ash aggregate are
basically the same as those for concrete that uses ordinary aggregate, but the following
characteristics apply.
a) The unit volume weight is between 1900 and 2100 kg/m3, which is approximately 10%
to 15% lower than that of concrete that uses ordinary aggregate.
b) The Young coefficient is between 10% and 20% smaller than the one for concrete that
uses ordinary aggregate.
c) In the same way as concrete that uses ordinary aggregate, the tensile strength
becomes larger as the compaction strength gets larger in moist conditions. However,
once the compaction strength exceeds 50 N/mm2, there is hardly any increase in tensile
strength.
d) The strength inherent with steel bars contained within the concrete is approximately
the same as with concrete that uses ordinary aggregate.
e) Fatigue strength is approximately the same as with concrete that uses ordinary
aggregate.
f) The shearing endurance levels of the bars that have not been fitted with reinforced
steel to prevent shearing and the shearing endurance levels of the surface members is
approximately 20% lower than that of concrete that uses ordinary aggregate.
Re: 2): When concrete that uses artificial fly ash aggregate is to be poured with
a pressure pump, it is necessary to inspect the performance of the pressure pump
thoroughly beforehand. It is necessary to use artificial fly ash with the surface dry in
order to acquire the expected performance levels of pressure pumps.
Re: 3): It is necessary to accumulate all information with regard to the
endurance levels of concrete structural objects that use artificial fly ash aggregate, and
it is also very important to store all records of the locations in concrete structures where
artificial fly ash aggregate have been used, and details on the concrete design.
119
The basic physiochemical properties of artificial fly ash aggregate and concrete that
uses artificial fly ash aggregate are to conform to Edition 106 of the Japan Society of
Civil Engineers Concrete Library, “Guidelines for the Design and Construction of
Concrete Structure that Uses Artificial Fly Ash Aggregate (Proposed).”
2) Usage Results
There are very few results available on concrete structures that use artificial fly ash
aggregate.
3) Supply
Very little artificial fly ash aggregate is produced, and supplies could be limited, so it is
necessary to investigate the availability of the required amount.
Not much carbon dioxide is emitted when concrete that uses artificial fly ash is used,
but it is emitted through the consumption of fuel and calcium during the manufacturing
process.
[Description]
RE 1):
Edition 106 of the Japan Society of Civil Engineers Concrete Library,
“Guidelines for the Design and Construction of Concrete Structure that Uses Artificial
Fly Ash Aggregate (Proposed)”, collects together the basic test chamber data of fresh
performance levels, hardness, and endurance levels of concrete that uses artificial fly ash
aggregate, and for implementing construction performance with pressure pump tests and
structural performance tests. There is very little alternative reference material available,
so it is necessary to thoroughly investigate the contents listed in this material before use.
RE 2):
There are results available for use in bridges. However, there are very few
results available for actual structures, so it is necessary to confirm that all of the
required performance levels of the applicable structure are fully satisfied before using
concrete that uses artificial fly ash aggregate.
RE 3):
Full-scale production of artificial fly ash aggregate has not started yet, and the
amount available on the open market is consequently limited. It is therefore necessary
to investigate whether the required amounts can be obtained.
120
When reusing this material, it is necessary to carry out thorough testing to
ensure that there are no problems with performance.
RE 4):
Carbon dioxide is emitted during the calcination of artificial fly ash aggregate
when it is being manufactured.
[Examples of Usage]
1) Reinforced concrete cable trough (factory-produced product)
2) Retaining walls for the recycled material storage area in a cement factory.
3) Main girders on the 2nd Tomei Expressway overpass (pre-tension method, hollow
simple slab system, PC bridge)
[Reference]
1) Japan Society of Civil Engineers Concrete Library Edition 106: Guidelines for the
Design and Construction of Concrete Structure that Uses Artificial Fly Ash Aggregate
(Proposed), August 2002
2) High-Performance Lightweight Concrete Research Committee, Japan Concrete
Institute: Symposium Thesis on the Diversity of Lightweight Concrete and Expansion of
its Use, August 2000
121
3.4. Crushing Processing
A new method of using clinker ash by crushing it into granules so that it is used
in the same way as fly ash.
3.4.1. Filler for Asphalt Paving
This section applies to the use of crushed clinker ash as filler for asphalt paving.
[Description]
This section applies to the use of crushed clinker ash as a substitute for JIS fly
ash.
The quality standards when using crushed clinker ash as filler for asphalt paving
must conform to the stipulations laid down in the Guidelines for Pavement Design and
Construction and the Paving Construction Guidelines.
The environmental safety standards and test methods when crushed fly ash is to be
used as asphalt filler must conform to the stipulations laid down in Section Two, 2.1.1
(2) 2).
[Description]
Re: 1) The test methods for all relevant quality factors stipulated in the quality
standards are to conform to the “Guidelines for Pavement Test Methods”. When
crushed clinker ash is to be used as filler for asphalt paving, it is necessary to confirm
that it satisfies the standards stipulated in JIS A 6201 “Concrete Fly Ash” and the
quality standards in the “Guidelines for Pavement Design and Construction” and the
“Pavement Construction Guidelines” shown in Tables 3.4.1-1 and 3.4.1-2.
Table 3.4.1-1. Particle size: particle size standards for crushed limestone granules
Size of sieve holes
Percentage passed
through (%)
600 µm
100
150 µm
90–100
75 µm
70–100
122
Table 3.4.1-2. Physical properties: fly ash, limestone and stone granules used as filler
Item
Evaluation standards
Plasticity index (PI)
4 or less
Flow test (%)
50 or less
Moisture absorption
4 or less
expansion rates (%)
Peeling test (%)
Pass
Re: 2): Conforms to the description provided in 1.1.1 (2) 2), Chapter 2.
(3) Technology Used
1) Design
The design formula for asphalt admixture that uses crushed clinker ash must conform to
the methods and procedures stipulated in the “Guidelines for Pavement Design and
Construction”.
2) Construction
The methods for blending and mixing asphalt admixture that uses crushed clinker ash
must conform to the stipulations laid down in the “Guidelines for Pavement
Construction”.
When using asphalt admixture that contains crushed clinker ash, the purchaser must
store all construction records, including material adjustment charts, construction
diagrams, and mixture design documentation, so that they may be used and referred to
when the asphalt is to be used repeatedly or disposed of.
[Description]
Re: 3): One point to remember during the blending design stage is that the
density of coal ash is low, and therefore density must be adjusted.
1) Quality Standards and test Methods
It is necessary to take into account the fact that performance levels differ from those of
the stone granules usually used.
2) Supply
It is necessary to consider the amount of material required during construction and the
method of storing it.
123
[Description]
RE 1): Coal ash granules are more spherical than stone powder, and the diameter of
the coal ash is smaller. Consequently, the Marshall stability test shows that there is a
tendency for the density to be higher, the porosity to be lower, and the saturation to be
higher. Therefore, the optimum amount of asphalt is smaller than when stone powder
is used. Thus, it is necessary to perform blending tests as asphalt aggregate and
performance tests on the aggregate (fatigue resistance, fluidity resistance, wear
resistance, peeling resistance, etc.), and ensure that quality standards are satisfied.
Results of the use of asphalt paving filler are shown in Table 3.4.1-3.
Table 3.4.1-3. Examples of results of the use of asphalt filler
Takehara
Takehara
domestic coal
domestic coal
domestic coal
Construction
Construction
Construction
Construction
Type
of private road of city road
Construction
Jan. 1982
Location
Shimonoseki
Shin-Utsunom Isogo
iya
Matsushima
domestic coal
overseas coal
overseas coal
Dec. 1982
Date
Construction
of private road of private road town road
Oct. 1982 to
Mar. 1983
Hiroshima
Hiroshima
Hiroshima
Apr.
to
of private road
Aug. Dec. 1985
1984
Jan 1983
Region
Construction of Construction
Kagawa
Fukushima
Okinawa
RE 2): It is necessary to ascertain that it is possible to acquire sufficient coal ash
for the scale of the construction work, and that it can be stored in a manner that
maintains quality levels.
[Reference]
1) Japan Fly Ash Association: Coal Ash and Its Uses (Mainly as Road Materials), April
1987
2) Japan Fly Ash Association: Report on Investigations into the Use of Coal Ash as Road
Paving Material, April 1989
3) Japan Fly Ash Association: Technical Manual relating to the above, April 1987
4) Japan Society of Civil Engineers: Current Situation and Perspectives on the
Technology for Using Coal Ash as Material in Public Works Projects—Improving
Landfills, Embankments and Foundations, April 1990
5）BVK Technical Documentation: A Granulate with Many Possibilities (Steag)
124
6) Von K.-H. Puch, W. vom Berg: Nebenprodukte aus kohlebefeuerten Kraftwerken,
VGB-Kraftwerkstechnik, 1997, Helt 7
125
4. Waste Wood
Overview of Waste Wood
The wood that is produced during construction work and demolition is known as
construction waste wood. This includes the trimmings and cuttings from construction
work in mountainous areas and branches and leaves from the periodical pruning of
roadside trees and bushes, and the waste wood and frameworks that cannot be reused
when structures are dismantled.
The construction waste wood that comes from dismantled houses contains
various types of wood in all shapes and sizes and wood composite materials. Therefore, it
is very difficult to combine it with other materials in order to reuse it, and this leads to
many cases where it cannot be recycled for economic reasons. Also, the wood trimmings,
thinned trees, and driftwood that are generated from the construction of dams or other
such structures have conventionally been processed by burning on the spot, but recent
legislation now prohibits open burning, which means there is an increase in the number
of cases in which these materials are handled as waste wood or construction waste wood.
The most common method of recycling waste wood is to shred it into chips for
reuse. This section explains the methods of shredding it into chips and using them as
mulch, cushioning material, pavement material for pedestrian paths, manufactured soil
(vegetation base material), and compost.
Demolition debris that is generated by dismantling structures is not covered in
this manual. Unlike the wood that comes from natural sources, demolition debris may
contain preservatives and other toxic chemicals, so it is necessary to give full
consideration to environmental safety when using it.
Although there is much documentation of the results of using thinned trees for
guard rails, sound-insulation walls, safety fences, and signboards, this manual deals only
with trees which were not thinned for construction and therefore are not regarded as
construction waste wood.
There are many cases where waste wood is shredded and made into chips for
recycling purposes, as shown in Table 4-1.
126
Table 4-1. Use and required processing of various types of waste wood
Simplicity levels of using waste wood*
Fallen or
Form of
Usage
Required processing
usage
Felled trees
Shear
blighted trees
Bark
ing
Twigs/
Trunk
Twigs/ Trunk
leaves
/roots
leaves /roots
Mulch
chips
shredded/chipped
△
△
○
△
△
○
Cushioning
chips
shredded/chipped
△
△
○
△
△
○
○
○
△
○
○
△
○
○
△
○
○
△
△
△
○
△
○
○
shredded/chipped Æ
Soil nutrients
compost
compost
shredded/chipped Æ
Manufactured
compost
compost Æ mixed with
other additives
soil for hillside
revegetation
shredded/chipped Æ mixed
chips
with other additives
*: ○ = used,
= not commonly used
The main types of waste wood and their characteristics are as follows.
(1) Felled Trees and Roots
—The tree trunks, branches, leaves, and roots that are generated during tree-felling
and root removal. Tree trunks and roots, which do not easily biodegrade, require a long
period of time to turn into compost, but they can be used effectively as supplements for
promoting tree growth if they are used without treatment after being shredded into
chips. However, in case where tree trunks are used as timber, they are not considered as
waste, so they are not covered within this manual.
As timber is biodegradable under anaerobic conditions when it is processed as waste
wood, it is treated as controlled waste. It is therefore necessary to consider using it in
aerobic conditions when it is to be recycled.
(2) Sheared Twigs and Leaves
—The twigs, trimmings, buds, and leaves that are generated during the periodic
shearing of trees and bushes. This material differs depending on the type of the tree and
the season in which it is generated (summer and winter), and the difference has effects
on processing and on the durability of the material after use, but it biodegrades easily
and is therefore suitable for use as compost.
127
(4) Fallen or Blighted Trees
—Trees and bushes that have fallen or died owing to aging, growth insufficiency,
natural disasters, or human intervention. The tree trunks can easily be used as timber
and they do not biodegrade easily, so they are not very suitable for use as compost.
(4) Bark
—The bark of coniferous trees, such as cedar and cypress, and of broadleaf trees, such
as oak and Japanese oak. The use of bark as a compost is very well known.
4.1. Shredding Process
(1) Types of Wood Eligible for Shredding
Wood shredding machines are designed for the purpose of shredding wood, but under
actual workplace conditions it is not uncommon for various non-wood materials to get
mixed in with the wood; they are categorized as easy-to-shred, difficult-to-shred, and
impossible-to-shred.
a) Easy-to-shred: branches, leaves, trunks, and roots
The stones that adhere to the roots may damage the bit spindles, so they must be
removed. All earth and sand adhering to the roots is also cleaned off to prevent
excessive wear on the blades.
b) Difficult-to-shred: grass, vines, and roots to which large amounts of soil adhere;
bamboo; and tatami mats
They may wind around the hammers, so it is better to shred them together with leaves
and trunks.
The earth attached to roots also tends to block up the holes in the screens, so it is
advisable to dry and remove it before shredding, or to mix it with branches and leaves
and process them together. Bamboo is not easily cut, and it has a tendency to wind
around the hammers.
c) Impossible-to-shred: stone slabs, metals
These materials are very difficult to shred with the use of wood-shredding machines.
(2) Composition, Shape, Size, and Use of Chips
Chips are produced by shredding them in a tab grinder or a horizontal shredder.
The shape, size and use of chips that are produced by shredding are shown in Table
4.1-2.
128
Table 4.1-2. Size and use of chips by screen size
Screen size
Chip size (mm)
(mm))
L×W×T
20
20 to 30 × 3 × 3
Livestock bedding, scattered
25
25 to 40 × 4 × 4
Livestock bedding, compost
38
38 to 55 × 6 × 6
Compost
50
50 to 75 × 8 × 8
Compost
65
65 to 95 × 10 × 10
100
100 to 150 × 12 × 12
General usage
Mulch
Mulch, hillside vegetation
Note: These chip sizes and production volumes may differ depending on the dryness of
the material before shredding. (The chips are slightly larger when dry and slightly
smaller when moist after shredding.)
4.1.1. Mulching and Cushioning Materials
This section applies to using chips that have been shredded from waste wood as mulch
for park areas and slope improvement projects, and as cushioning for park pathways,
plazas, and play areas.
[Description]
When chips shredded from waste wood are to be recycled on the spot, they can
be used as both mulching and cushioning material.
- Mulch
This is generally known as wood chip mulch, and it is currently used throughout the
country as mulch for covering parkland and pathways (on streets), in cultivation
projects to improve the land, and on bare soil to suppress weeds, retain soil moisture,
maintain soil temperature, and prevent the loss of soil. As it has the same organic
properties as the mulch that has been conventionally manufactured, it is attracting
attention as being effective for supplying soil with nutrients and for improving the
physical properties of soil (cushioning, softening tread pressure, water retention, etc.)
- Cushioning
This is used to cover the ground areas around athletic courses and play equipment, and
it can be used as a surface for park pathways, as it is comfortable to walk on. Laying the
cushioning around play equipment reduces injury in the event of falls, and therefore
increases the safety of all users. Its placement around the roots of old cherry-blossom
trees to alleviate soil compaction is also on the increase.
129
The name of the raw material, the maximum sizes, and the particle size are marked on
the quality display tags for both mulching and cushioning materials. Quality standards
and test methods can be established depending on the necessity.
When waste wood (other than raw wood) that is thought to contain toxic materials is to
be used as raw material, it necessary to investigate the environmental safety of the
chips.
The efflux of toxic materials must satisfy the effluent standards stipulated for 26 of the 27
substances (excluding copper) shown in Appendix 1 of this manual or in the Appendix of “On
Environmental Quality Standards for Soil Pollution” (Ministerial Announcement No. 46,
Ministry of Environment, August 23rd, 1991) and effluent limits stipulated in Clause 1 and
2, Article 18 of “Enforcement Regulations of the Soil Contamination Countermeasures
Law” (Ministry Ordinance No. 29, December 26th 2002, Ministry of Environment)
(hereinafter referred to as the Effluent Standards.).
The toxic content of materials must satisfy the content standards stipulated for the nine
substances laid down in Clauses 2 and 3, Article 18 of “Enforcement Regulations of the Soil
Contamination
Countermeasures
Law” (Ministry Ordinance No. 29, December 26th
2002, Ministry of Environment) (hereinafter referred to as the Toxic Content Standards).
(2) Test Methods
Effluent test methods must conform to the methods stipulated in the table of the “On
Environmental Quality Standards for Soil Pollution” (Ministerial Announcement No. 46,
Ministry of Environment, August 23rd, 1991).
Toxic content tests must conform to the methods stipulated in the table in “Measurement
Methods Concerning Toxic Content in Soil” (Ministry Ordinance No. 19, March 6th, 2003,
Ministry of Environment) (hereinafter referred to as the Toxic Content Standards)
The only waste wood products that can be used are those for which effluent tests have been
implemented on each lot and the results thereof are marked on the supplied quality display
tag.
130
[Description]
Re: 1): The quality levels of mulch and cushioning are supplied with lists
providing information on the base material of the chips (tree type, region), the particle
size of the shredded chips, and the shape of the shredded chips. Although these are
thought to have effects on erosion, dispersion, durability, and ease of handling, no
standards have been stipulated for usage. Chips with a maximum size of 50 mm or less
are generally used.
Re: 2): Chips made from felled trees, thinned trees, pruned trees, and fallen
trees, which exist in the natural environment and do not contain any heavy metals, are
safe to use from the environmental point of view. However, there are cases where wood
from dismantled buildings and structures has been treated with pressure-injections of
toxic agents, such as preservatives and insect repellants (copper chrome arsenate, or
CCA), in order to maintain the durability of the material. If it is not possible to
determine whether or not the chips are made from wood that contains such agents, then
it is necessary to give full consideration to environmental safety. Although the amount
of CCA being used has dropped off, the arsenic, chrome, and copper that it contains
cause sewer pollution.
The permissible levels of effluent and contents as standards for environmental
risk evaluation are shown in Appendix 4. When compiling “Environmental Quality
Standards for Soil Pollution” and “Enforcement Regulations of Soil Contamination
Countermeasures Law”, a list as shown in Table 4.1.1-1 is drawn up. The effluent and
content amount obtained from tests must satisfy these evaluation standards.
131
Table 4.1.1-1. Standards for environmental risk evaluation
Item
Effluent Standards
Toxic Content Standards
Cadmium
0.01mg/l or less
All cyanogen
Organic phosphorous
Lead
0.01mg/l or less
150mg/kg or less
Chromium hexavalent
0.05mg/l or less
250mg/kg or less
Asenic
0.01mg/l or less
150mg/kg or less
0.0005mg/l or less
15mg/kg or less
Total mercury
Alkyl mercury
None
ＰＣＢ
None
Dichloromethane
0.02mg/l or less
0.002mg/l or less
1,2-dichloroethane
0.004mg/l or less
0.02mg/l or less
Cis-1,2-dichloroethylene
0.04mg/l or less
1mg/l or less
0.006mg/l or less
Trichloroethylene
0.03mg/l or less
Tetrachloroethylene
0.01mg/l or less
1,3-dichloropropene
0.002mg/l or less
Thiuram
0.006mg/l or less
Simazine
0.003mg/l or less
150mg/kg or less
( Free cyanide ) 50mg/kg or less
Thiobencarb
0.02mg/l or less
Benzene
0.01mg/l or less
Selenium
0.01mg/l or less
150mg/kg or less
Fluorine
0.8mg/l or less
4,000mg/kg or less
For safety management purposes, the manufacturer must submit a quality
display chit that lists all of the required items as shown in Table 4.1.1-2 at the time of
shipping chips in order to guarantee quality.
132
Table 4.1.1-2. Items required in safety quality displays
No.
Required item
(1)
Brand and material thereof
(2)
Name of manufacturer
(3)
Name of manufacturing plant
(4)
Date of manufacture or date of shipping
(5)
Lot number
(6)
Quantity
(7)
Quality assurance display (indicates the quality
assurance levels for the items listed in Table
4.1.1-1, such as cadmium: 0.01 mg/l or less; lead:
0.01 mg/l or less
(8)
Miscellaneous (particle size, physical
characteristics, results of effluent tests, etc.)
Safety inspections are to be carried out at the time of shipping by the
manufacturer and at the time of delivery by the purchaser. The inspection at the time of
delivery is to be implemented in accordance with the test results created by the
manufacturer, or the purchaser is to inspect the test values in order to confirm everything
independently. In this case, the method of extracting samples for the sample tests is to
conform to the stipulations laid down in JIS Z 9015, “Procedures for Discreet Value
Sample Inspections”.
(3) Technology Used
Although no regulations exist for wood chips when they are used in construction or as
mulch or cushioning, layers with a thickness of between 5 and 15 cm consisting of
chips that conform to the shape and size regulations stipulated for each particular
usage are to be used.
[Description]
No general construction and application standards exist for the use of wood
chips, but results are available from where contractors have approached each project
individually in accordance with the conditions at the site. Installation examples indicate
that chips shredded through a screen with hole diameters of approximately 100 mm and
133
laid with a thickness of around 10 cm are most common. However, as the frequency of
use with cushioning material is greater, leading to swifter deterioration, common
examples involve usage of a slightly thicker layer of approximately 15 cm and
replenishing it every year.
1) Environmental Safety
There is concern for the effects that the lixivium from shredded chips, which is
emitted during the biodegradation process, may have on the surrounding
environment and the risk of fire outbreaks it poses when the chips are used without
treatment as mulch or cushioning.
For accumulating and compiling application results, it is necessary to clarify the
design standards for the chips to be used as mulch or cushioning material and the
quality standards of the chips by each use. It is also necessary to investigate the
effects of mulch as weed-resistant and dryness-resistant materials in comparison
with conventional mulching materials.
3) Usage Results
Statistical data covering the situation through usage results is not available on a
nationwide basis.
4) Repeated Use
Woodchips biodegrade and decompose over a period of several years, so they are not
suitable for reuse.
[Description]
RE 1):
When chips are made from thinned trees that exist in the natural environment, there
is little concern about toxic substances eluted from or contained within the chips.
However, when the chips are used in depressions or marshes, which easily collect water,
tree sap eluted during biodegradation can be collected, and therefore it is necessary to
consider the risks this may have on surrounding trees. They also pose a risk of fire
outbreaks through discarded cigarette ends etc. Although fire outbreak is uncommon
with chips made from the wood gathered through periodical pruning, the bark of cedar
and cypress trees contain fibers that can sustain fires, and there are many cases where
phosphate has to be used as fire-resistant agent. The abnormal outbreak of harmful
insects and bacteria with the ability to harm nearby trees must also be considered. It is
important that we investigate whether or not such outbreaks occur in the future.
134
RE 2):
Depending on differences in the particle size and layer thickness of chips, there are
cases where they are easily blown away by the wind or displaced by rain (floating away).
Establishing quality standards to regulate countermeasures, design standards, and
usage standards for each use must be considered for the future. Also, as wood chips
have a tendency to biodegrade and decompose over several years, it is necessary to
replenish the chips periodically (once or twice a year) if their effects are required on a
permanent basis. Mulching material is currently applied to suppress weeds, to retain
soil moisture, to help maintain soil temperature, and to prevent soil loss. It is necessary
to determine the quantitative effects of the mulching material in the future.
RE 3):
A remarkably large number of examples of the use of chips as mulch and cushioning are
thought to exist. However, statistical data covering conditions through usage results is
not available on a nationwide basis.
RE 4):
Woodchips biodegrade and decompose over several years, so they are not suitable for
reuse.
(1) Supply
Supplies are available throughout the country. However, it is necessary to investigate
availability if it is to be used in large quantities.
(2) Necessity
It is necessary to emphasize the use of woodchips as a way of reducing the burden on
the environment and of circulating resources.
[Reference]
1) Maruma Technica Co., Ltd.: Homepage: http://www.maruma.co.jp/
2) Kenichiro Fujizaki, Takehiko Katsuno, Shuzo Hasegawa, Shigehito Muranaka, Ryoji
Suzuki: Bio-Degradation of Wood Chip Mulch, Abstracts, 28th Japanese Society of
Revegetation Technology Research Conference, 1997
3) Green Softscience Co., Ltd.: Vegetation Bases Made from Trees—Development
Methods and Application Examples—Using Vegetation Resources, 1998
135
4.1.2. Pedestrian Pavement
This section applies to the construction of pedestrian paths using wood chips.
[Description]
This is a technology that uses chips that have been made from felled trees,
removed roots, and periodically trimmed branches on pedestrian pathways. This places
very little burden on the environment and creates pedestrian pathways that blend well
into the scenery. The main components of this are chipped wood material and binder,
but there are cases where sand is mixed in. The material used as the binder includes
epoxy resin, polyurethane resin that hardens in moist conditions, and improved asphalt
emulsion. By changing the ratios of these materials during blending, it is possible to
tune the elasticity to the intended use.
It is necessary to evaluate (1) the ratio of wood material to be used, (2) walking comfort,
(3) durability, (4) economic viability, and (5) color tone in order to verify whether the
mixture of chipped wood satisfies the quality levels required for the pedestrian
pavement concerned.
To conform to the stipulations laid out in 4.1.1 (2) 2), Chapter 2.
[Description]
Re: 1): The characteristics and quality standards of construction methods that
provide the basic functions required for garden paths and pedestrian pavement using
wood chips are listed below.
(1) The surface course of the pavement must be resistant to slipping to ensure that all
pedestrians can walk safely.
(2) It must not contain areas where water accumulates and hinders passage.
(3) It must have sufficient strength to withstand the weights stipulated in Category I of
Pedestrian Pathway Pavement Designs laid down in the Manual for Design and
Construction of Asphalt Pavement (paths used by both pedestrians and bicycles, and
bicycle paths.)
(4) It must be resistant to cracking and fragmenting caused by climatic conditions.
(5) It must be resistant to malformation caused by abrasion.
(6) It must not be much more expensive to install than existing pedestrian paths, and it
136
must be economically viable.
(7) It must blend well with the surrounding scenery.
The evaluation items, standards, and methods are shown in Table 4.1.2-1.
Table 4.1.2-1. Evaluation items, evaluation standards, and evaluation methods
Evaluation
Evaluation
items
standards
The main
The main
trees that have been
material
material must be
chipped
must be wood
wood (chips, wood
Quality standards
(1) Wood material from
Evaluation methods
- Volume ratio of the wood
used as the surface course.
fiber, etc.)
(2) Must possess basic
functions required for
Walking
- The
- Skid-resistance test with
skid-resistance
the use of a pendulum skid
garden paths and
value must be
resistance tester.
pedestrian paths
40 BPN in wet
- Surface hardness test.
conditions.
- GB and SB test.
comfort
- Must not contain
areas in which
- Water permeability test.
- Water-drainage.
water
accumulates
and hinders
passage.
Durability
No extreme
- Counterblow test
damage is caused
- Freeze–thaw test, and the
by the weight of
counterblow test thereafter
traffic or climatic
-Durability test, and the
conditions.
-Low-temperature
counterblow test
(3) Must use products with
excellent economic
viability
Economic
viability
Must not be much
- Cost of construction
more expensive to
- Construction manual
construct and
- Repair manual
maintain paths
than existing
pavement
methods that
137
consider local
scenery.
(4) Must harmonize with
Color tone
the surrounding scenery
Products for
- Joint tests
which color can be
- Construction photographs
adjusted
- Blending chart
Note: BPN: British Pendulum Number; GB: golf ball; SB: steel ball
The various test standards and the number of test samples per construction are shown
in Table 4.1.2-2.
Table 4.1.2-2. Details of verification tests
Test samples
Test item
Standards
(per
Remarks
construction)
Skid-resistance test with the
Guidelines for
use of a pendulum
Pavement Test
skid-resistance tester
Methods
Surface hardness test
JIS A 6519
3
wheel tracking test
3
Guidelines for
Elasticity test (GB and SB test)
Same samples used for
Pavement Test
3
Methods
wheel tracking test
wheel tracking test
Guidelines for
Counterblow test (ambient
temperature at 20 °C)
Pavement Test
Methods, Addendum
3
Marshall test
Booklet
Freeze–thaw test, and the
Durability test, and the
Guidelines for
Pavement Test
3
Methods Appendix 5
JIS B 7754
3
Marshall test
Marshall test
Guidelines for
Counterblow test (low
Pavement Test
temperature at 5 °C)
Methods, Addendum
3
Marshall test
Booklet
Note: Samples used for the wheel tracking test (30 cm × 30 cm × 5 cm)
Samples used for the Marshall test (φ10 cm × 5.0–6.5 cm)
138
Next, the quality control measures shown in Table 4.1.2-3 are to be implemented for
evaluation of path safety when the pathways are constructed.
Table 4.1.2-3. Quality control tests for wood chip pavement
Name of test
Test methods
Slip-resistant test Guidelines for
Target values
BPN 40 or more
Pavement Test
Methods
Onsite water
Guidelines for
Water permeability coefficient
permeability test
Pavement Test
1 × 10–2 cm/s
Methods
GB and SB tests
Guidelines for
Same level as elastic asphalt
Pavement Test
admixture
Methods Separate
Appendix
Re: 2): Must conform to the description provided in 4.1.1 (2) 2), Chapter 2.
(3) Technology Used
1) Material Used
The materials to be used as wood chip pavement material must conform to the standard
regulations or be of a quality that is superior to the standard regulations, unless
otherwise specified in the design documents.
2) Design
The subgrade construction for wood chip pavement must conform to the stipulations
laid down in the Guidelines for Pavement Design and Construction and the Manual for
Design and Construction of Asphalt Pavement. Although the wood admixture blend will
differ depending on the binder and pavement construction methods used, the blend
must conform to specifications.
3) Construction Method
The construction of wood chip pavement must be carried out under appropriate quality
control methods with regard to blending, mulch coverage, rolling, curing, and the like.
[Description]
Re: 1): The subgrade material for wood chip pavement must conform to the
stipulations laid down in the Guidelines for Pavement Design and Construction and the
139
Manual for Design and Construction of Asphalt Pavement. The main material used in
the surface course must consist of wood chips, along with binder and sand. Although
wood chips are used with a diameter mostly of between 2.0 and 3.0 cm, there are
examples of chips shredded further and used as wood fiber with a diameter of 1.0 cm or
less. The products being used as binder include epoxy resin, polyurethane resin that
hardens in moist conditions, and improved asphalt emulsion. A breakdown of the
materials that use epoxy resin as the binder are shown in Table 4.1.2-4.
Table 4.1.2-4. Material used
Material name
Shape and type, etc.
Wood chips
2.5–3.0 cm
Special epoxy resin
Density ~1.1 (g/cm3)
Special epoxy resin
Coarse sand
Re: 2): Since the surface course of pedestrian paths that use wood chips require
different blends depending on the binder and pavement construction methods used, a
blending chart must be confirmed and clearly mentioned in the design documentation.
An example of a blend that uses epoxy resin as the binder is shown in Table
4.1.2-5.
Table 4.1.2-5. Example of design blending
Material name
Blend (mass
Blend (volume
ratio %)
ratio %)
Wood chips
32
85.1
Special epoxy resin (main
10
3.5
10
4.2
48
7.2
component)
Special epoxy resin
(accelerator)
Coarse sand
A cross-sectional diagram of the pavement configuration is shown in Fig. 4.1.2-1.
Fig. 4.1.2-1. Cross-sectional diagram of a pavement configuration
140
Re: 3): The general flow of construction work for wood chip pavement is shown
in Fig. 4.1.2-2.
Foundation laying
Frame placement
↓
Wood chip delivery & crushing
↓
Material blending
↓
Material carried
out for
transportation
↓
Construction
(shaping)
(rolling)
(finishing)
↓
Curing
↓
Completion
Fig. 4.1.2-2. Flow of wood chip pavement construction
The details of each process and the points to be considered are listed below.
(1) Preparations: The foundation laying must be completed evenly with the use of a
roller plate or the like to ensure that the required thickness of the pavement can be
obtained. It is necessary to pay attention to height and lateral expansion of the edge
lines when placing the framework.
(2) Wood delivery and crushing: The wood chips can be shredded either at the place
where felled and fallen trees are collected or at wood chip factories, and then delivered
to the location where they are to be used. The delivered wood chips, coarse sand, and all
other materials must be covered to protect them from the effects of weather.
(3) Material blending: The materials in their calculated proportions are placed in a
141
container, and the appearance and volume are then inspected. Blending is to be carried
out in a mortar mixer first. The wood chips are put into the mortar mixer first, then the
other pre-mixed binder ingredients are added and mixed for approximately 1 additional
minute. Then the coarse sand is added and mixed for another minute. As special epoxy
resin is used in the blending procedure, make sure that the mixture does not come into
contact with the skin, and wear long-sleeved work clothes, protective glasses, masks,
rubber gloves, and an apron during this task.
(4) Material discharge and transportation: When it is confirmed that the ingredients
have been mixed together evenly, the mixture is removed from the mortar mixer. A light
truck or other small vehicle is used to transport the mixture if access is possible, and a
public vehicle is used if not accessible.
(5) Construction: The transported material is shaped with the use of a metal or wooden
rake to ensure even coverage. Once it has been laid, it is covered with curing plates, and
rolled to attain an even path surface. Subsequently, a tamper or a wooden rake is used
to smooth out all visible irregularities.
(6) Curing: The entire path surface is covered with a curing sheet to protect it from rain
or inclement weather, and the edges of the sheet are locked with anchors. The amount of
time required for curing is approximately 12 hours in summer and approximately 24
hours in winter.
The frequency of effluent tests and toxic content tests to confirm the physical
properties and environmental safety of the pedestrian pavement requires future
examination.
2) Usage Results
Although examples of using wood chips for pavement are increasing, they have still not
spread throughout the country.
3) Supply
Since the agricultural industry is facing the problem of disposing of thinned trees
owing to the prohibition of open-air fires, there should be no problem obtaining
enough material.
The manufacturing process involves shredding felled trees and roots into wood
chips, which are then joined together with binder, so no carbon dioxide is emitted.
142
[Description]
RE 1):
It is necessary to implement the tests shown in Table 4.1.2-2 to verify that the basic
functions as garden paths or pedestrian paths are satisfied (walking comfort, durability),
and it must be verified that the paths conform to the stipulations laid down in the
Guidelines for Pavement Test Methods for skid-resistance, elasticity, water permeability,
durability, and weather-resistance. In other words, the physical performance
requirements must be the same as those demanded of paths made using new material.
Investigations into the requirements of the physical performance levels which are
unique to recycled materials are to be considered in the future.
RE 2):
There are very few results available with regard to wood chip pavement. However,
various organizations throughout the country are using wood chips experimentally, and
the number of examples of actual usage is on the rise. It is expected that usage centered
around local autonomous authorities will increase.
RE 3):
The construction industry also faces the problem of disposing of thinned trees owing
to the prohibition of open-air fires, so there should be no problem obtaining enough
material in all regions.
RE 4):
The manufacturing process involves shredding felled trees and roots into wood chips,
which are then bound with binder, so no carbon dioxide is emitted.
Although there is no problem with regards to environmental safety if no chemical
compounds, such as pesticides, adhere to felled trees and roots, it is important to
confirm this with tests. If these tests provide stable results, then it is possible to reduce
the frequency of the tests.
(2) Repeated Use
As decomposition sets in a few years after usage has commenced, it is difficult to
reuse wood chips.
The cost of construction is slightly higher than the cost of other pavement
construction projects that consider the surrounding scenery. This point must be
investigated in the future.
143
Pavement must not be remarkably more expensive to install than existing pedestrian
paths, and it must be economic viable.
(4) Necessity
Although the amount of felled trees available is increasing owing to the prohibition of
open-air fires, applications are limited. It is necessary to initiate investigations and
make all necessary preparations in the construction industry.
[Reference Material]
1) Development of Pavement Construction Methods that Use Wood Resources—
Oakwood Pavement, Construction Technology Evaluation Certification No. 97201
2) Development of Pavement Construction Methods that Use Wood Resources—Wood
Fiber Pavement, Construction Technology Evaluation Certification No. 97204
3) Development of Pavement Construction Methods that Use Wood Resources—Color
Ashwood Pavement, Construction Technology Evaluation Certification No. 97206
4) Wood Chip Pavement Technology Documents (Kumagai Gumi Co., Ltd.)
4.1.3. Manufactured soil
There are two major ways to use waste wood to manufacture soil. The first is to
incorporate wood chips that have not been turned into compost (hereinafter referred to
as raw chips) into soil with fertilizer. The second is to shred and compost the waste wood,
and then add sub-materials, such as clay, and slow-acting fertilizer.
4.1.3-1. Raw Chip Manufactured Soil
This section applies to the use of waste wood shredded into chips that have not been
composted to manufacture soil.
[Description]
Several methods are available for using raw chips. The first is where the raw
chips are used in part or in whole as a substitute for bark compost or other organic
materials that are scattered over ordinary soil. In this case, the chips are shredded
finely to a diameter of approximately 5 to 15 mm. The second method is to lay a cover of
chips with a diameter of approximately 150 mm over sloping land and then scatter
seeds over the top of this. The third method is to mix the chips with topsoil that has
been gathered on-site to improve soil aeration and water-retention and provide a
favorable foundation for growing vegetation.
144
The third method has acquired Construction Technology Evaluation
Certification. The basic procedure for this method is shown in Fig. 4.1.3-1.
The quality standards when raw chips are used on slopes, which gauge the erosion
resistance of plants as slope protection or the growth of plants, must conform to the
same performance levels as the quality standards required for conventional slope
vegetation methods.
Conforms to the stipulations laid down in 4.1.1 (2) 2), Chapter 2.
[Description]
Re: 1):
(1) Quality Standards
It is necessary to test the material and construction management methods in
order to verify required performance levels. If the standards for determining plant
growth on slopes are not satisfied after construction has been completed, additional
fertilizer must be added until the objectives for vegetation are achieved.
However, when raw chips are mixed into soil, growth is initially slower than
with ordinary tree-planting methods, but normal growth levels are attained later. If it is
difficult or impossible to use the conventional growth judgment standards shown in the
table, judgment must be postponed for a few months before checking again.
The standards for growth judgment are outlined below.
Growth Standards
- Determination Period
There are remarkable differences in
vegetation growth depending on the
time and place of installation.
A: Warm zones with no frost
B: Warm zones
C: Warm zones with snowfall
D: Cold zones
E: Cold zones with snowfall
F: Severely cold zones
Okinawa is zone A
The periods when growth should be
determined after planting are shown by
zone and planting period in Fig. 4.1.3-2
and Table 4.1.3-1. However, these
periods are based on grasses and
papilionaceous shrubs, and tall trees
whose growth cannot be estimated are
omitted.
Fig. 4.1.3-2. General zone categorization for planting regions
Fig. 4.1.3-2.
145 General zone categorization for planting regions
Table 4.1.3-1. Growth determination periods
Period
Zone
A
Spring
Summer
Fall
Winter
(Planted between
(Planted between
(Planted between
(Planted between
June and
October and
December and
March and May)
September)
November)
February)
60 days after
beginning to
beginning of May
middle of May to
planting
middle of
in the following
beginning of
November
year
June
(Planted between
B
(Planted between
(Planted between
October and
April and June)
July and
November)
60 days after
September)
middle of May in
planting
mid-November
the following
year
(Planted between
C
(Planted between
(Planted between
mid-September
April and June)
July and
and October)
60 days after
September)
middle to end of
planting
mid-November
May in the
following year
(Planted between
December and
March)
end of May to
mid-June
(Planted between
November and
March)
middle to end of
June
(Planted between
(Planted between
D
April and June)
90 days after
planting
(Planted between
July and August)
mid-November
September and
(Planted between
October)
November and
beginning of June
March)
in the following
beginning of July
year
(Planted between
E
April and June)
90 days after
planting
(Planted between
(Planted between
September and
July and August)
October)
mid-November
middle to end of
June in the
146
(Planted between
November and
March)
beginning of July
following year
(Planted between
(Planted between
May and June)
F
90 days after
planting
(Planted between
July and August)
mid-November
September and
October)
beginning of July
in the following
year
Note #1: The growth of vegetation is determined by the number of trees that have grown
if before the period of sprouting, and by the general coverage after the period of
sprouting.
Note #2: Decisions to be made together with supervisors in the case of abnormal
climatic conditions.
- Growth Determination
There are several methods of determining growth depending on the objectives of
tree-planting and the period of installation. A yardstick for determining growth 3
months after planting is shown in Table 4.1.3-2.
Table 4.1.3-2. Yardstick for determining growth after sowing
Evaluation
Growth levels 3 months after planting
shrubs confirmed for every square meter.
- Vegetation coverage rates at 50% to 70%, and 5 or more trees or
shrubs confirmed for every square meter.
- Grass coverage rates at 70% to 80%, and 1 or more trees or shrubs
deferred
Decision
confirmed for every square meter. In this case, postpone judgment
until the following spring.
- New shoots can be seen here and there, but the entire slope is
mostly bare. In this case, postpone judgment for 1 to 2 months.
- The soil has been washed away, and there is no hope for vegetation
Impossible
type
Tree & shrub vegetation
Possible
- Vegetation coverage rates at 30% to 50%, and 10 or more trees or
growth. In this case, the foundation needs to be reconstructed.
- Grass coverage rates at 90% or more, but no sign of any trees or
shrubs. In this case, check the situation and take appropriate
action after cutting the grass.
147
ible
deferred
slope appears green from a distance of 10 m.
- Approximately 10 shoots can be seen per square meter, but growth
is slow. In this case, wait for 1 to 2 months or until growth levels
reach 50% to 70% before judgment.
- The soil has been washed away, and there is no hope for vegetation
growth. In this case, the foundation needs to be reconstructed.
le
Poss
Decision
Impossib
Grassland type
- Vegetation coverage rates at 70% to 80% or more and the entire
- Vegetation coverage at 50% or less.
Note #1: Situations will differ depending on the time that has elapsed since construction
has been completed.
Note #2: The tree and shrub vegetation type tends to appear bare during winter owing
to leaf loss, so the inspection should be carried out the following spring.
(2) Quality Test Methods
The test methods for the quality items stipulated for the growth determination
standards are to be carried out while referring to the stipulations laid down in “Road
Earthwork—Guidelines for Stable Slopes and Inclines” issued by the Japan Road
Association. Refer to 1) in Reference for details on all other quality test methods.
Re: 2): To conform to the descriptions laid down in 4.1.1 (2) 2), Chapter 2.
(3) Technology Used
1) Design Methods
The design methods applicable to using raw chips for planting vegetation on hillside
slopes must conform to the most commonly used design examples for which results are
available.
The main materials for tree-planting projects that use sprinkled chips and topsoil
include shredded chips and topsoil gathered on-site. Soil that is most suitable for the
growth of local vegetation is to be produced and then spread on the site accordingly.
[Description]
Re: 1): Protecting hillside slopes for the purpose of only planting trees has no
effect in preventing structural damage, such as landslides, so it is necessary to initiate
separate investigations into ensuring the structural stability of the slope. This
148
technology therefore does not exceed the boundaries of design methods aimed only at
satisfying the performance levels of soil.
The method of growing vegetation by spreading raw chips and topsoil on the
ground is applicable not only for cleared hillsides and inclined embankments, but also
for slopes with a wide range of soil conditions, such as on bedrock and on areas that
have no soil nutrients or no soil at all. Also, if this method is used in combination with
slope restoration work (the material is spread on the ground immediately after the slope
restoration work has been completed, section by section) on inclines subject to severe
wind or severe erosion, it is extremely effective in providing protection for the slope
within a short period of time.
The soil that is created with this method has an aggregated structure, so the
topsoil that contains the microorganisms and seeds of plants that grow in the local area
can be used. It is therefore easy to encourage the growth of shoots from a wide variety of
tree, shrub, and grass seeds to restore the locality back to its original condition.
Examples of the standard design methods that are applicable for use with the
tree-planting method that uses raw chips and topsoil are provided in Table 4.1.3-3.
Table 4.1.3-3. Examples of Standard Design Methods
Design
Remarks
standards
When the gradient
Use of metal
supports
of the slope is less
Sandy soil to soft
layer
rock
Soft rock to hard
rock
Gradient of slope
13 m or less (18 m or
Range of
less)
construction
(note #1)
No
than 15°
All other gradients
Thickness of
Metal supports are required on slopes
13m or more
that are subject to freezing or heavy
frost, even if the gradient is less than
Yes
t = 7 cmm
15°.
Including embankments
t = 10 cm
Gentle slopes
Thick metal supports, fences, or other
less than
slope protection devices are required
1:0.8
if the gradient is steeper than 1:0.8.
Possible
The figure in parenthesis is the
Reverse-
permissible length when a long-boom
wound
backhoe is used as the base machine.
construction
149
Material
fluctuation
30%
rates
Investigations required for special
cases, such as flat land.
Note #1: Construction is possible on three or four stages of the slope if the ground is to
be constructed with the spreader suspended from a mobile crane.
Re; 2): When raw chips are to be used, it is necessary to mix them with other
materials in accordance with the blending chart to ensure that it contains appropriate
amounts of soil for the optimal growth of vegetation.
The method of making soil with raw chips and topsoil uses shredded chips from
trees cut down in the local area and topsoil taken from the actual site. It is therefore
necessary to plan the acquisition of the required amount of material from the local area
and the period of installation for every process of the work before it is implemented. It is
especially important to plan in detail each step of the construction work when the
earthwork is to be carried out simultaneously.
- Planning the Use of Felled Trees
Felled trees that have no value or that cannot be used as timber, roots that pose
processing problems, and branches and leaves are shredded into chips and recycled. It is
necessary to have a full understanding of the period when trees eligible for reuse are to
be felled, the period when they are to be chipped, and the period when they are to be
used in each area, and then draw up plans for recycling the chips. It is also necessary to
fully consider the method and site of storage in order to limit the onset of
biodegradation and erosion.
- Planning the Use of Topsoil
It is necessary to fully understand and draw up a recycling plan well in advance of the
period of collecting and using topsoil, as well as the usable amount. It is also necessary
to survey the suitability of the soil for vegetation. Not only is topsoil suitable for
tree-planting, but can also restoring an area with embedded seeds. Therefore, it is
important to carefully choose and collect the soil.
The procedure for selecting local topsoil is shown in Fig. 4.1.3-3.
150
Local topsoil (topsoil)
Soil condition judgment
No
(1) Must not contain any properties that hinder the growth of vegetation.
(2) Fine particle content (0.075mm or less) = 20% or more of the total
volume.
(3) Gravel content (20mm or more) = 40% or less of the total volume.
(4) Soil acid degree (H20) = 4.5 to 8.0
Improvement Process
(1) Add clay
(2) Remove gravel
(3) Remove all properties that hinder
the growth of vegetation
Yes
Aggregation test (indoor)
No
Confirm the aggregate
condition
Yes
Fig.4.3-3. Procedure for Selecting Local Topsoil
Re: 2): Information must be collected on the types of trees, categories of leaves
(e.g., broadleaf and coniferous), the type of local soil (topsoil or excavation residue),
and whether sludge has been used or not, together with all data available on the
condition of the soil after construction and the growth of vegetation, and stored as
construction journals.
Occasionally, initial growth is slow when raw chips have been used, but care must
be taken not to sow additional seeds or add more fertilizer.
The local topsoil contains microorganisms and seeds, so new growth due to the
151
improved soil will become apparent. As this vegetation may not match the
predetermined objectives of the tree-planting project, it is consequently necessary to
give careful consideration to the topsoil that is selected and the seeds with which it
is primed.
2) Supply
The raw material from which the chips are made is specified as industrial waste
under the category of “waste wood”. Therefore, it is necessary to make sure that all
laws and regulations relating to the Waste Disposal and Public Cleansing Law
and/or other relevant laws and regulations are strictly observed, and that the
material is handled in an appropriate manner.
3) Repeated Use
Soil produced by using chips and topsoil bio-degrades and returns to nature over
time, so it cannot be used repeatedly.
[Description]
RE 1):
As growth is relatively slow in the initial construction period (approximately 3 to 4
months), conventional growth determination standards can indicate poor growth, which
in certain cases leads to the need to reseed or add more fertilizer. However, this is a
feature of non-composted raw chips when they are used in manufactured soil, and later
normal growth has been verified, so it is recommended that growth patterns be left up
to nature, and additional seeds and fertilizer not be used.
RE 2):
The raw material from which chips are made is specified as industrial waste under the
category of “waste wood” and should therefore be processed at controlled final disposal
sites. It is necessary to make sure that it is handled in an appropriate manner that
conforms to the Waste Disposal and Public Cleansing Law.
Waste wood that is generated on-site and can be directly recycled is not covered by the
Waste Disposal and Cleansing Law and is therefore easy to reuse. However, some
restrictions on such usage are specified in waste-related laws and regulations, and it is
necessary to pay close attention to these laws and regulations. Waste wood that is
transported to different locations from where it was generated and chips that were
delivered from an external source for recycling purposes may be covered by the Waste
Disposal and Cleansing Law depending on the case, so it is necessary to hold
consultations with all parties concerned before the material is used.
RE 3):
152
Soil produced by the use of chips and topsoil gradually biodegrades and returns to
nature over time, so it cannot be reused. However, that is the same where new
materials are used in vegetation projects on hillside slopes, so this is not deemed to be a
problem.
As the majority of the material used is recycled, as the chips need only to be shredded
and not turned into compost, as local topsoil is used instead of imported topsoil, and as
construction methods are mostly mechanized, it is possible to create soil at a cost of
between 10% and 30% of conventional material spreading operations.
(5) Necessity
This reuse is necessary order to reduce the burden on the environment and to encourage
recycling.
The fuel consumed by the many machines that are required for construction results in
carbon dioxide emissions, but apart from this there is no cause for anxiety.
[Reference]
1) Kumagai Gumi Co., Ltd.: Root Chip Construction Method, Slope Vegetation Method
Using Felled Trees, Report on Advanced Construction Technology Inspection
Certification, Advanced Construction Technology Center, March 1999
2) Root Chip Construction Research Institute: Root Chip Construction Technical
Documentation, April 2001
3) Susumu Yokotsuka, Masahiro Kobayashi, Masami Ishida, Masamichi Takahashi,
Akio Akama, Seiichi Ota: Chemical Properties of Soil on Slopes to Which
Non-Biodegraded Chips Are Used and Subsequent Growth, 32nd Japanese Society of
Revegetation Technology Symposium, September 2001
4) Susumu Yokotsuka, Masahiro Kobayashi, Shigeru Saito, Seiji Hosoe: Vegetation on
Slopes with Soil that Uses Non-Biodegraded Chips, Part One: Decomposition of Chips
and the Status of Nitrogen in Soil, 56th Annual Meeting of the Japan Society of Civil
Engineers, October 2001
5) Japan Road Association: Road Earthwork—Guidelines for Stable Slopes and Inclines,
March 1999
153
4.1.3-2. Compost as Manufactured Soil
This section applies to mixing clay or other materials with composted wood chips, and
spreading it on slopes as soil.
[Description]
Waste wood that has been delivered to composting plants or composting yards
and then shredded, turned into compost, and mixed with clay or other sub-materials
and slow acting fertilizer can be used as soil.
This compost-based soil is mixed with a binder to strengthen the connections
between materials and the ground and to prevent the soil from being eroded or washed
away by rain or being damaged by being frozen.
The general procedure for manufacturing compost-based soil is shown in Fig.
4.1.3-4.
154
Trees felled and roots
extracted
↓
Transported to composting plants or
composting yards
↓
Shredding process
↓
Composting process
↓
Maturity judgment
↓
Blending (volume
increased)
↓
Property
analysis
↓
Slow-acting fertilizer added; weighed
and packed in bags
↓
Delivered to
site
Fig. 4.1.3-4. Procedure for manufacturing compost-based soil
Compost-based soil must satisfy the quality standards for manufactured soil. The
material and facilities must be periodically inspected in order to confirm this.
To conform to the stipulations laid down in 4.1.1 (2) 2), Chapter 2.
[Description]
Re: 1): Compost-based soil is blended to satisfy the quality standards in Table
4.1.3-4.
155
Table 4.1.3-4. Quality standards for compost-based soil (dry value)
Item
Unit
Standard value
Remarks
Total nitrogen (N)
%
1.0 or more
Fertilizer analysis
method
Total carbon (C)
%
C/N ratio
Cation exchange
40 or more
"
40 or less
"
Mol (+)㎏-1 40 or more
"
capacity (CEC)
pH
−
5.5 to 8.0
"
Moisture
%
60 ± 10
"
Particle diameter
mm
10 or less
"
The quality standards for compost-based soil are assessed in a chemical
analysis test.
The analysis method must conform to one of the following:
-
Details on the Fertilizer Analysis Method 2nd Edition (Edited by Masayoshi
Koshino, Yokendo, May 1989)
-
Soil Nutrient Analysis Method (Supervised by the Agriculture, Forestry and
Fisheries Research Council, Yokendo, December 1970)
-
Analysis Methods for Compost and Other Organic Substances (Agriculture,
Forestry and Fisheries Promotion Council, March 1985)
-
Soil Physical Measurement Methods (Yokendo, April 1972)
Tests are carried out on compost-based soil to determine whether it satisfies
the quality standards for manufactured soil. As there are differences in quality between
products, it is also necessary to carry out quality control at all stages of manufacture.
The quality tests shown in Table 4.1.3-5 are to be implemented. In addition to
these tests, it is necessary to run the tests when any modifications are made to the
material or the machinery.
Table 4.1.3-5. Quality test items
Item
Facility
Frequency
Material weighing machines
Once a year
inspections
Standard
Confirm that the waste wood has When the composting process is
material tests turned into compost
complete (3 to 4 months after it has
156
been laid)*
Quality tests on the composted
Once per lot
waste wood
Quality tests on crushed cultured Once per lot
seashells and other additives
Product tests
Chemical property and
Once per lot
environmental safety tests
* The size of each lot is to be determined in accordance with the scale of production and
fluctuations in the quality of the material.
It is necessary to confirm that the results of the quality tests on compost made
from felled trees and roots and the results of the tests on chemical properties in the
product satisfy the quality standards stipulated in Table 4.1.3-4.
Daily quality control measures must be implemented to guarantee quality
levels.
Re: 2): Must conform to the descriptions provided in 4.1.1 (2) 2), Chapter 2.
(3) Technology Used
1) Design Methods
The basic construction using compost-based soil uses a diamond-shaped metal mesh,
and reinforced frameworks must be used depending on the stability of the hillside. The
thickness of the layer spread and the blend of seeds must also be determined in
accordance with the objectives of vegetation.
Compost-based soil must be made in several predetermined processes, including
cleaning the slope, laying the metal mesh, placing the anchor pins, and spreading the
tree-planting material.
[Description]
Re: 1): Compost-based soil makes an excellent base for growing vegetation,
having excellent erosion resistance on hillside slopes (with a gradient of 1:0.5 or less)
that consist of bare bedrock or excavated rock (as long as they do not exceed the
ecological limits for the growth of organisms), and is the ideal material for improving
the appearance of bare hillsides and helping nature return to its original condition.
Except where quality standards are stated specifically in the design
documentation, the materials used for compost-based soil must conform to the
standards shown in Table 4.1.3-6, and must be of an equal or superior quality.
157
Table 4.1.3-6. Example of materials used
Material used
Standards
Diamond-shaped
φ2 mm, 50 mm × 50 mm m2
Unit
metal mesh
Main anchor pins
φ16 mm, L = 400 mm
No. of
pins
Auxiliary anchor
φ9 mm, L = 200, mm
pins
No. of
pins
Manufactured soil Compost-based soil
L
Binder
High-molecular resin
kg
Material for
Clay minerals
kg
adjusting
maturity and
moisture levels
Seeds
set
Re: 2): It is necessary to initiate thorough investigations into the following
stipulations with regard to the installation of compost-based soil, and make sure that
all requirements are strictly adhered to.
(1) Preparation
The condition of the site must be checked in accordance with the prescriptions laid down
in the design documentation, and construction must be carried out accordingly. The
items that require checking include the locations of starting and ending construction,
the existence of spring water, cracks in the bedrock, and other abnormalities.
(2) Installation Procedure
a) Slope Cleaning
All garbage, fragmented rock, tree stumps, and weeds must be removed from the edges
and surface of the slope, and extreme unevenness caused by crumbling rock must be
repaired. All unstable rocks must be removed from the surface of the slope immediately
after the ground has been tilled, if necessary.
b) Metal Mesh
A diamond-shaped metal mesh must be laid gradually from the edge of the slope until it
covers the entire area of construction. A minimum of two mesh units (100 mm) must be
used for all overlapping areas.
c) Anchor Pin Knocking
Some 30 main anchor pins must be knocked in every 100 m2, and approximately 150
158
auxiliary anchor pins must be knocked in every 100 m2 to fix the metal grid in place.
d) Measurement of Material to Spread
The amount of material (containing seeds and binder) is measured in accordance with
the stipulation in the blending design chart.
e) Spreading the Manufactured Soil
After the compost-based soil has been mixed with the binder and seeds, it is to be
conveyed to a spreader on a conveyor belt and then spread with air-pressure. A
suspension agent consisting of maturity- and moisture-adjustment solutions must be
sprayed with an air pump at the same time so that it flows into the manufactured soil
approximately 3 m from the nozzle. A rapid binder may also be added if necessary. The
spreading work is to be carried out while adjusting the angle and distance of the nozzles
to match the shape of the surface on which the material is being spread.
1) Physiochemical Properties and Environmental Safety
Physical property tests to verify that the tree-planting material serves the function
as manufactured soil and tests to confirm environmental safety must be
implemented.
2) Usage Results
There are very few results available for compost-based soil, but the number of
examples is beginning to increase with regional maintenance bureaus.
3) Supply
Although sufficient amounts of raw materials can be easily obtained, a certain
amount of time may be required for the composted chips depending on the area.
Bio-gas is emitted during the composting process, but most of this is carbon
dioxide that has been generated through aerobic biodegradation.
[Description]
RE 1):
There are no problems with environmental safety as long as no pesticides or other
chemical substances are contained in the wood and roots. However, it is necessary to
confirm the safety with tests when many different types of waste wood are used.
To make sure that the compost-based soil satisfies the quality conditions demanded of
manufactured soil, it is necessary to implement the confirmation tests shown in Table
159
4.1.3-4. Also, this construction work can be carried out at any time of the year, but
appropriate amounts of water and heat are required to ensure the budding and growth
of vegetation. Therefore, it is recommended that construction be avoided during severe
winters and during periods of intense heat. Certain tree species are particularly slow to
bud and grow, and vegetation that has not attained a certain level of growth can die off
during the winter. Therefore, it is appropriate to carry out the construction work from
the summer months onward.
RE 2):
There are not many results available for the use of compost-based soil, but the
number of examples is increasing at regional maintenance bureaus in the Kanto and
Shikoku regions. The number of results attained by local autonomous bodies is expected
to increase further.
Re 3):
Agricultural and other industries are experiencing problems with processing thinned
trees now that the law banning open-air incineration has been proclaimed, so it is very
easy to obtain the required amounts of waste wood. However, several months are
required for the composting process, so a certain amount of time may be required before
the required material can be acquired, depending on the area.
RE 4):
Carbon dioxide is emitted during the composting of felled trees and roots. As this
carbon dioxide is generated through biomass, it is not covered by the protocols on
reducing the emission of greenhouse gases.
(1) Repeated Use
As compost-based soil eventually blends in with the local ecosystem, base material
itself cannot be recycled.
This differs depending on the source of the supply. Production costs are higher than
the price of compost available on the open market when felled trees and roots are to be
composted on site, but prices fluctuate depending on supply and demand.
(3) Necessity
This is a necessary construction method in order to reduce the burden on the
environment and to create recycling society.
160
[Reference]
1) Raito Kogyo Co., Ltd.: “Double-Chip Eco-Cycle” Vegetation Base That Makes the
Effective Use of Shredded and Composted Felled Trees and Roots, Report on Technical
Inspection Certification, Construction Technology Verification No. 0125, Public Works
Research Center, March 2002
2) Nishimatsu Construction Co., Ltd.: “Root Recycling Method” Slope Tree-Planting
Construction That Makes the Effective Use of Vegetation Material Generated on Site as
Compost, Report on Technical Inspection Certification, Technology Verification No.
1401, Advanced Construction Technology Center, April 2002
3) Japan Recycled Vegetation Association: Recycled Vegetation PMC Construction
Manual, http://www.japan-recycle.com/pdf/pmc-kaisetu.pdf, April 2004
4) Nobuo Fujiwara, Takehiko Ishizaka, Atsuko Ishizone, Koichi Morizaki, Yasuo Iizuka:
Investigation into Manufacturing Method of Compost Made from a Mixture of Sewage
Sludge and Pruned Branches and Leaves (Public Works Research Institute, Ministry of
Construction) Public Works Research Institute Documentation No. 3708, 2000
5) Atsuko Ishizone: Test Construction of Vegetation Base Using Sludge and Pruned
Branches Compost, Public Works Research Institute Documentation Vol. 44. No. 1,
January 2002
6) Yoshiyuki Sato, Tetsuya Watanabe: Manufacture of Vegetation Base That Uses
Felled Trees, Highway Technology, No. 19, April 2001
7) Masayuki Kitazono: Slope Earthwork from Surveys to Design, Japanese Geotechnical
Society, October 1997
8) Nobuji Namba: Actual Vegetation, Sobunsha, 1986
161
5. Waste Glass
Overview of Waste
Waste glass includes the waste window glass generated when dismantling
buildings, the waste glass generated during glass manufacturing processes, defective
glass, and used glass containers that are generated by wholesalers and retailers.
As can be seen in Table 5-1, glass bottles account for the majority of glass
products manufactured on a nationwide basis in 2003, and this is followed by the plate
glass used in buildings and vehicles, television tubes, fluorescent lighting and glass used
in kitchen appliances such as bulbs, and glass fiber used in FRP products or the like and
the total of produced glass was 2.31 million tons.
Table 5-1. Amount of Glass Products Manufactured (2003)
Item
Comparison
Product
Amount (tons)
Composition
Total Sum
with
Ratio
(¥)
Previous
Year
Total
2,308,701
100.0%
368,412
100.0%
626,402
27.1%
154,836
42.0%
8,003
0.3%
2,834
0.8%
1,560,159
67.6%
148,671
40.4%
Kitchen utensils
66,321
2.9%
28,803
7.8%
Vases, ashtrays
4,545
0.2%
2,029
0.6%
43,271
1.9%
31,239
8.4%
2,237,835
97.0%
337,580
91.6%
70,866
3.0%
30,832
8.4%
Basic Glass Products
Glass for scientific and
medical use
Containers
(glass
bottles)
Other glass products
Industrial
produce
[Total]
Domestic
[Total]
produce
Source: Research and Statistics Department, Economic and Industrial Policy Bureau,
Ministry of Economy, Trade and Industry
162
Of all the glass products, the products that were recycled most commonly
were glass bottles. The majority of colorless and brown glass is converted into cullet
and reused in glass bottles, but the amount of green and black bottles produced is
quite small so recycling here has yet to make any progress. Owing to this, the
development of technology to promote the reuse of waste glass in fields other than
glass bottles, such as tiles, blocks, ultra-lightweight aggregate and asphalt pavement
aggregate, has advanced, and actual usage results have been recorded.
The mill ends of plate glass used in buildings and vehicles that are generated during
the factory manufacture are crushed and then reused as cullet by glass
manufacturers. Glass that has been used in windows is not collected. However,
advances have recently been made in reusing the glass that is generated when
buildings are dismantled as the raw materials for tiles and blocks, and progress has
also been made in the collection and recycling of TV and PC screen tubes and
fluorescent lighting. The collection of the glass used in vehicles from shredder dust
has also begun, and investigations are currently underway to establish methods of
removing window glass used in vehicles when vehicles are scrapped for the purpose
of recycling.
163
Glass cullet is sorted glass bottles that are finely crushed and then classified by
particle size. In addition to being used as the base material for glass manufacturing,
this is also used for various purposes, including use as material for construction projects,
public works projects and for industrial products.
According to data compiled by the Japan Association of Glass Manufacturers
(see Fig.5.1-1. Ratio of Glass Bottle Production Volume and Cullet Usage), the use of
glass cullet is increasing on an annual basis, and this reached approximately 90.3% by
2003. There is a huge social demand for the development of methods of using glass
cullet in large volumes for the purpose of preserving resources, saving energy and
reducing waste, and surveys have been initiated in recent years to establish methods of
using glass cullet as pavement material, and various methods towards this end have
already being implemented.
Fig.5.1-1. Ratio of Glass Bottle Production Volume and Cullet Usage
（1）Overview of Process
An example of the glass cullet crushing system for crushing glass bottles and
classifying them by particle size is shown below.
164
Fig.5.1-2. Example of a Glass Cullet Crushing System
The composition and properties of glass bottles and plate glass are shown in
Table 5.1-1 and Table 5.1-2. Although the composition and properties are almost the
same, cullet made from glass bottles of any color other than colorless (brown, green, blue,
black) cannot be reused for plate glass. Also, as colorless glass plate has more impurities
than glass bottles, there are restrictions to prevent the use of plate glass cullet in glass
bottles, which means that glass bottles and plate glass are not compatible.
Table 5.1-1. Composition of Glass Bottles and Plate Glass (By Color)
Glass Bottles
Properties Black
Plate Glass
Brown Green Blue
Colorl Float
Plate
ess
colorles glass
(Trans
parent
s
)
transpa ss
Heat
Heat ray
ray
absorpti
colorle absorp on
rent
tion
bronze
transp blue
arent
72.83
71.40
71.53
71.34
70.87
71.10
1.80
A12O3
1.83
2.43
2.20
2.23
2.30
1.47
1.58
1.47
1.47
Fe2O3
0.03
0.24
0.11
0.15
0.16
0.07
0.07
0.37
0.18
TiO2
0.01
0.03
0.02
-
0.01
0.03
0.04
0.03
0.03
GaO
11.00
10.47
10.67
10.17
11.10
8.91
MgO
0.11
0.37
0.30
0.83
0.22
4.04
Na2O
12.63
13.67
13.43
13.30
13.33
13.10
K2O
0.96
1.17
1.10
1.11
1.40
0.83
0.84
0.86
SO3
0.21
0.08
0.24
0.17
0.21
0.24
0.24
0.20
SiO2
10.32
2.47
12.40
71.40
8.85
3.75
13.30
71.21
8.84
3.91
13.33
0.79
0.26
Note: Created from the “Glass Composition Databook (1991 Edition)” edited by the Japan
Association of Glass Manufacturers
165
Table 5.1-2. Properties of Glass Bottles and Plate Glass (By Color)
Glass Bottles
Properties
Black
Trans
Brow
n
paren
Plate Glass
Gree Blue Col Float
Plate
Heat
Heat ray
n
orle
colorle glass
ray
absorpti
ss
ss
colorless absorp on
t
transp transpa tion
arent
Softening
730
718
725 724 726
568
558
563
88
92
91
734
rent
bronze
blue
738
729
730
554
545
545
91
90
90
Point (Deg.C)
Slow Cooling
563 564
549
Point (Deg.C)
Heat Foaming
90
92
91
Coefficient
(X10-7/Deg.C)
Note: Created from the “Glass Composition Databook (1991 Edition)” edited by the Japan
Association of Glass Manufacturers
Also, the typical properties of glass cullet are shown in Table 5.1-3.
Item
Property Values
Density
Approximately 2.45 to 2.55 (g/cm3)
Moisture
Approximately 0 to 0.3%
Absorption
Particle size
Large
amounts
with
a
particle
diameter of crushed-rock size #5,#6
and #7
Abrasion Loss
Approximately 40 to 50%
Stability
Approximately 0.2%
Table 5.1-3. Typical Properties of Glass Cullet
166
The recycling system for glass bottles includes the returnable bottles that are washed and
then reused, and the one-way bottles that are crushed and used as the base material for
manufacturing new bottles, and both of these methods are used as effective methods of
preserving resources. Glass cullet is the name given to glass bottles that are sorted into
type and crushed into fine powder, which is then sorted again in accordance with the size
of the particles. In addition to being used as the raw material for glass manufacturing,
glass cullet also has a wide range of uses, including use as material for construction
projects, public works projects and for industrial products.
5.1.1. Paving Subgrade Materials
This section applies to the use of glass cullet, which has been produced by finely
crushing sorted glass and separating it in accordance with particle size, as subbase
course aggregate. To determine if the aggregate is suitable for use on roads with a
paving design traffic volume of 1,000≦T, (vehicle/day or direction)it is possible to refer
to either existing results or implement test construction.
[Description]
There are very few examples of glass cullet made from crushed glass being used
as paving subgrade material. However, this does have certain advantages over using it as
surface course aggregate, such as the ability to be recycled repeatedly and the fact that it
poses no technical problems like peeling away from asphalt, etc. The use of this as
subbase material is applicable for roads with a road paving design traffic volume of
T<1,000 (vehicles/day or direction) and can be used up to an equivalent of the B traffic
stipulated in the former manual of road pavement, so if it is to be used on roads or in
subbases with a traffic volume that exceeds the above traffic amount, then it is necessary
to confirm durability and other factors beforehand.
167
(2) Test Methods
The quality standards for subgrade material that uses glass cullet must conform to the
stipulations laid down in the “Guidelines for Pavement Design and Construction” and the
“Guidelines for Pavement Construction”, etc.
The methods of testing the quality items stipulated in the quality standards are to
conform to each relevant method laid down in the “Guidelines for Pavement Test
Methods”.
The environmental safety standards, test methods and management methods of glass
cullet used as subgrade material must conform to the stipulations laid down in 1.1.1. (2)
2), Chapter 2. In other words, effluent tests and toxic content tests on six substances must
be implemented.
[Description]
Re: 1): There are no recorded results of subgrades that use only cullet because
of the particle size of glass cullet. When cullet is mixed with crusher-run and natural
granule subgrade material or used as subgrade stabilization material, the mixture must
satisfy the quality standards of subbase course material (Table 1.1.1-4, 1.1.1, Chapter 2).
The results of actual usage in this case indicate that it is desirable to keep the mixture
ratio of cullet to 15% or less.
Re: 2): Glass is a non-organic material that is very similar to the composition of
the rocks used as construction materials. As it is manufactured by being melted at
temperatures of 1,000 degrees Celsius or higher, it contains very little toxic materials
that may affect environmental safety. The cullet that is used in subgrades must
consequently have its environmental safety levels confirmed by implementing effluent
tests and toxic content tests on six substances, similar to the case of molten slag and the
like. The details of this conform to the descriptions provided in 1.1.1. (2) 2). There are
cases where the matters that cling to glass bottles may lead to the detection of toxic
effluents. It is therefore necessary to ensure that they are washed thoroughly when
glass cullet is manufactured.
168
(3) Technology Used
1) Design
The design of subgrades that use glass cullet must conform to the methods and
procedures laid down in the Guidelines for Pavement Design and Construction.
2) Construction
The construction of subgrades that use glass cullet must conform to the methods and
procedures that correspond to the construction method laid down in the Guidelines for
Pavement Construction or the like.
3) Maintaining Journals and Repeated Use
When subgrades that use glass cullet are constructed, the purchaser must save all
construction diagrams, quantity charts and other design documentation together with the
results of the tests carried out on the subgrade material so that they are available for use
when the material is to be reused or disposed of.
Glass cullet contains no properties that fluctuate greatly by its usage, so there are no
problems if the glass cullet is recycled and reused.
[Description]
(1) Results of Usage
According to a report of test construction conducted for pavement in japan,
subgrade material consisting of 50% of cullet and 50% of size-controlled crushed stone
possesses the durability which is almost the same as that of generally used subgrade
materials.1). Documentation also exists stating that glass bottles and other subgrade
rock were crushed and then used as subgrade material in Texas, America, and that
favorable results were obtained as it caused no damage to the tires of hauling trucks2).
An example of a test construction carried out in the Koto Ward, Tokyo, in
which glass cutlet produced from finely crushed empty bottles was recycled for use as
subgrade material is shown in Fig.5.1.1-13). This test construction involved a 30cm-thick
subgrade which includes a mixture of RC-40 crushed road-building rock and glass cullet
which was used as a 15cm-thick layer of subbase course, and the surface course
consisted of a 10cm-thick layer of asphalt concrete. Three types of subgrades awere
constructed: two of which contained crushed stone of which ratio of glass cullet was 15%
and 50%, respectively, while 100% 0f glass cullet, instead of mixture of glass cullet and
crushed stone, was mixed with 11kg/m２ of cement for the other case.
169
Fig.5.1.1-1. Example of a Test Construction of a Subgrade Using Glass Cullet3)
The following information was obtained from the results of a survey during the
test construction work.
a) A ratio of 15% is suitable for glass cullet to be mixed into the subbase material judging
from the easiness of construction, bearing value, and the like.
b) Using glass cullet that has been processed with cement is slightly difficult for use in
construction (especially the rolling process), but the required levels of bearing value are
attainable.
c) The bearing value of paving that uses glass cullet in the filler layers is slightly weaker
than conventional paving methods (CBR 20%).
d) Required levels of construction performance and bearing value are attainable when
glass cullet is used as backfill.
(2) Supply
Plants that process waste glass bottles and manufacture cullet are concentrated in
urban areas, so it is necessary to implement an investigation to ensure that the amount
of cullet that is required for local work can be obtained.
(3) Repeated Use
Glass cullet contains no properties that fluctuate greatly during usage, so there are no
problems pertaining to it being recycled and reused.
It is difficult to mix cullet into subgrade material on site, so this must be carried out at
plants, which makes it more expensive than conventional subgrade construction.
(5) Necessity
The construction industry is attracting the most attention for the use of recycling waste
glass bottles as a material other than that for manufacturing new glass. Recycling
waste glass into subgrade material for use in pavement uses vast amounts of waste
glass, and if improved technology can be established, this will lead to the recycling of
170
green bottles into glass cullet; the type of glass least used for recycling purposes.
Glass cullet is manufactured by crushing waste glass into fine particles and then
sorting it by particle size, and only the electric power required for these two processes
leads to the emission of carbon dioxide.
There are very few examples of glass cullet being used as material for paving
subgrades, so it is necessary to make the effort to accumulate data on usability,
durability, economic viability and other factors, and grasp a full understanding on
long-term usability.
1) Green Japan Center: Report on the Foaming of Businesses Making Use of Waste
Material (Application and Development of Glass Cullet as a Road Paving Aggregate,)
March 1994
2) Roger L. Engelke：City Finds Cutting Edge to Recycling Glass、West Age, Feb 1, 1997
3) Kohei Kimura, Hideo Amino, and Takanobu Haritani: Use of Glass Cullet as Subgrade Material and Backfill, 23rd Japan Road Association Conference
General Thesis Collection, pages 152 to 153, October 1999
5.2. Crushing and Calcination Processes
(1) Overview of Process
The manufacturing process of tiles and blocks that use recycled glass in the shape of
recycled waste cullet is carried out as explained below. As glass can be incinerated at
low
temperatures
of
1,000
degrees
Celsius
(conventionally
temperature
of
approximately 1,200 degrees Celsius) the manufacturing process helps reduce the
amount of carbon dioxide emitted and the amount of energy used.
1) Crushing Process
The cullet is washed and then crushed into particles of a predetermined size in a
crusher. The process up until this has been explained already in 3.1. The subsequent
processes include adjusting the color tone and turning the glass into powder so it can be
reused as raw material. Clay and binder are then added automatically to this powder
from a resource tank, and it is mixed into an even mixture of liquid soil (a state in which
shaping is possible) in a mixer.
171
2) Molding Process
The fluidity of the liquid soil mixture is controlled as it is poured into molds of the
required dimensions with a high-pressure press and then pressure-molded.
3) Calcination Process
The molded tiles are transported to the heat-resistance setter, where they are calcinated
in a roller-hearth kiln. Calcination is carried out at a temperature of approximately
1,000 degrees Celsius, and the temperature inside the kiln is compartmented into areas
and controlled accordingly to prevent warping and cracking.
Fig.5.2-1. Example of the Manufacturing Process of Recycled Glass Tiles3)
1) Physical Properties
A chart comparing the physical properties of tiles processed through the
crushing and calcination of recycled glass against other construction material (ceramic
tiles, stoneware tiles, concrete tiles) is shown in Table 5.2-1.
172
Table 5.2-1. Physical Properties of Recycled Glass Tiles
Physical Property
1)
Recycled Glass Tiles
Ceramic Tiles
Stoneware Tiles
Moisture absorption
1.5%
Bending strength
2
20.6N/mm
2
(210kgf/cm )
2
19.6N/mm
2
(200kgf/cm )
2
14.7N/mm
2
(150kgf/cm )
Abrasion Loss
0.04g
0.04 to 0.08g
0.04 to 0.09g
Skid resistance
77 to 97 BPN
35 to 60 BPN
45 to 70 BPN
Chemical resistance
Acid/Alkali 3%
Acid/Alkali 3%
Acid/Alkali 3%
No abnormality
No abnormality
No abnormality
300 cycles
10 cycles
10 cycles
Freeze/thaw
resistance
1%
No abnormality
Bulk density (g/cm3)
5%
No abnormality
2.32
2.2 to 2.4
Concrete
15%
2
4.9N/mm
2
(50kgf/cm )
60 to 80 BPN
No abnormality
2.1 to 2.3
2.2 to 2.4
Note #1: Test methods conform to JIS A 5920 ceramic tiles.
#2: BPN = British Pendulum Number (portable skid resistance tester)
As all sharp edges are eradicated during the crushing and calcification
processes, these tiles have the same safety levels as ceramic tiles and fired tiles when
they are being used. Controlling the particulate size and color of the cullet during the
crushing and adjustment processes provides the same freedom of design as is offered by
ceramic and other tiles. Climate resistance is also the same as ceramic tiles.
Fired tiles, glass and other items are included in the non-combustible materials
stipulated by Clause 9, Article 2 of the Building Standards Law. Waste glass is also
non-combustible, similar to ordinary glass.
2) Chemical Properties
The composition of tiles produced by crushing and calcinating waste glass is shown in
Table 5.2-2.
Table 5.2-2. Composition of Recycled Glass Tiles (Mass %)
Al２O３
SiO２
Propert
Fe２O３
CaO
MgO
K２O
Na２O
y
Content
65 - 70
10 - 20
1.0 - 2.0
5.0 - 7.0
1.0 - 2.0
1.0 - 2.0
7.0 - 9.0
5.2.1. Tile Blocks
This section applies to pavement and tiles for surface finish, blocks, bricks and roadway
barrier blocks, etc., that are made from glass cullet for use in public works structures.
[Description]
173
Tiles and blocks made from recycled glass are generally used for the following purposes.
(1) Tile Products
External wall tiles for public works structures.
(2) Block Products
Calcinated blocks, bricks and roadway barrier blocks, etc., used in parks and pavements.
However, concrete blocks and interlocking blocks are excluded. See 4.1.3, Chapter 3 for
details on interlocking blocks.
The dimensions, strength and other physical properties
stipulated in the JIS standards shown below must be
satisfied.
(1) Tiles
Must conform to JIS A 5209 “Ceramic Tiles”.
(2) Bricks and Blocks
Must conform to JIS R 1250 “Ordinar Bricks”, “Flat Slabs for pavement” and
“Boundary Blocks for Roads” in Category I of JIS A 5371 “Pre-Cast Plain Concrete
Products”.
The environmental safety standards, test methods and safety management standards
for glass cullet made from waste glass must conform to the stipulations laid down in
1.1.1. (2) 2), Chapter 2. In other words, effluent tests and toxic content tests
stipulated on six substances must be implemented, and the measured effluent
amounts for the specified toxic substances must be below the environmental
standards.
[Description]
Re: 1): The related JIS quality standards are shown in Tables 5.2.1-1 to 5.2.1-5.
Tests must be carried out in accordance with test methods of the relevant JIS standards
in order to confirm quality levels. The results on the tests must be listed on the quality
display tag.
Table 5.2.1-1. Bending Strength of JIS A 5209 “Ceramic Tiles”
174
Nominal Designation and Category
Indoor Tiles
Outdoor
Tiles
Floor Tiles
Mosaic Tiles
Wall Tiles
Floor Tiles
Tile dimension (*) of
155mm or less
Tile dimension (*) of
more than 155mm
Bending Fracture Load for each 1cm Width
(kgf/cm)
12{1.23} or more
60{6.12} or more
80{8.16} or more
100{10.20} or more
120{12.24} or more
60{6.12} or more
Note (*): Tile dimension refers to the longer side of rectangular tiles or one side of
square tiles.
Table 5.2.1-2. Bending Strength of “Flat Slabs for Pavement” in Category I, JIS A
5371 “Pre-Cast Plain Concrete Products” (for reference only)
Bending
Type
Strength
Span L
Load
Exposed Surface
Nominal
Code
KN
mm
Processing Method
Designation
300
12
Ordinary Flat Slab
N
330
13
300
12
Color Flat Slab
C
240
400
16
300
12
400
16
Washed Flat Slab
W
450
18
300B
5
480
450B
7.5
300
12
240
400
16
Cast Stone Flat Slab
S
450
18
300B
5
480
450B
7.5
Table 5.2.1-3. Quality of JIS R 1250 “Ordinary Bricks”
Moisture
Type 2
Type 3
Type 4
15 or less
13 or less
10 or less
15.0 or more
20.0 or more
30.0 or more
Absorption
Rates (%)
Compaction
Strength
N/mm2
Table 5.2.1-4. Bending Strength of “Boundary Blocks for Roads” in Category I, JIS A
5371 “Pre-Cast Plain Concrete Products” (for reference only)
Type
Bending Strength Load kN
Nominal
L=600mm,
Code
L=2,000mm
Designation
1,000mm
175
Single-lane roadway
barrier block
Two-lane roadway
barrier block
Estate Road Boundary
Block
Single
Both
Ground
A
B
C
A
B
C
A
B
C
23
40
60
24
42
63
6.5
8
13
12
21
31.5
12.5
22
33
−
−
−
Table 5.2.1-5. Performance of JIS A 5406 Architectural Concrete Blocks (reference only)
Moist
Compaction
Compac
Bulk
Category
ure
Compaction
Strength of
Permeabi
tion
Air-Dry
by
Absor
Strength
Front
lity (*)
Strengt
Density
Cross-sect
ption
Category
Cross-Section
ml/m2-h
h
3
(g/cm )
ion
Rates
Code
Area N/mm2
N/mm2
%
08
−
4 or more
Less than
1.7
−
−
12
−
6 or more
Less than
1.9
16
−
8 or more
10 or
Hollow
less
20
20 or
Block
more
−
25
25 or
8 or
−
more
less
30
30 or
more
20
20 or
10 or
300 or
more
less
less
25
25 or
8 or
more
less
Mold
30
30 or
−
−
Block
more
35
35 or
6 or
more
less
40
40 or
more
Note (*): Permeability only applies to waterproof blocks.
Re: 2): The environmental safety standards and test methods conform to the
descriptions laid down in 1.1.1 (2) 2), Chapter 2.
(3) Technology Used
1) Design
Tile design is to conform to special specifications or the descriptions provided in the
Architectural Construction Standards for JASS19 “ceramic tiles construction”.
2) Construction
176
Tile construction procedure is to conform to special specifications or the descriptions
provided in the Architectural Construction Standards for manufacturing JASS19
ceramic tiles.
The packaging used with tile products must make it clear that the tiles contain
recycled material, and design records must be maintained regarding their usage.
When tiles made from recycled glass that have been used once are to be reused again
in the future as raw material for recycled tiles, they may be handled in the same way as
normal tile material and reused accordingly.
[Description]
Re: 1): As tiles made from recycled glass contain the same properties as similar
tiles used in construction projects, it is possible to use conventional design methods.
Special specifications are to be used if they are available, but if not, design is to conform
to the descriptions provided in the Architectural Construction Standards of JASS19
“ceramic tiles construction”.
Re: 2): As tiles made from recycled glass are calcinated at a temperature of
approximately 1,000 degrees Celsius, they are similar to JIS A 5029 ceramic tiles and
may therefore be used in accordance with conventional methods. Special specifications
are to be used if they are available, but if not, construction is to conform to the
descriptions provided in the Architectural Construction Standards of JASS19 “ceramic
tiles construction”.
Re: 3): The packaging used with tile products made from recycled glass must
make it clear that the tiles contain recycled material. Also, the design diagrams and all
other documentation must clearly state that recycled products have been used. Recycled
glass tiles that have been used once may be used again as long as there are no scratches
or other damage.
（4）Points for Consideration
1) Physiochemical Characteristics
As they contain performance levels that are equal to or superior to similar kind of
construction materials, there are very few problems involved with their usage.
However, it is necessary to make sure that foreign matters and toxic substances are not
contained in products that used cullet.
2) Results of Usage
A certain amount of results are available in both the public sector and private
sector, so products that have been manufactured by plants for which results exist are to
be selected.
177
3) Supply
They are sold throughout the country, but it is necessary to initiate investigations
to ensure that the required amounts can be obtained.
Carbon dioxide is emitted during the calcination process, but as calcination is carried
out at low temperatures in order to reduce the amount of carbon dioxide emissions, the
amount emitted is less than that emitted during the manufacture of conventional tiles.
[Description]
RE 1):
Recycled glass tiles and blocks that have been subject to crushing and calcination have
superior or same levels of strength and durability (weather-resistance, fire-resistance)
than similar construction materials (ceramic tiles, stone tiles, concrete tiles, etc.,), and
therefore cause very few problems. As long as the required performance levels satisfy
the standards laid down in the JIS standards there is no problem with usage, but it is
very important to select products manufactured by plants that carry out quality control
on a daily basis. It is advisable to select plants that have been inspected and verified by
public organizations and use the products that they supply. A topic attracting attention
at the moment is the stabilization of the quality of cullet through crushing technology,
glass color separation and the removal of foreign matters, etc.
RE 2):
According to a survey carried out by the Public Works Research Institute (implemented
in December 2002,) only one case of recycled tiles being used in paving was reported.
However, it is safe to believe that more cases exist considering the usage results in the
field of architecture. Also, the Handbook of recycled Material for Construction
(December 2000) published by the then Ministry of Construction reports many cases of
these tiles being used in the private sector. When using recycled glass tiles and blocks
that have been subject to crushing and calcination, it is necessary to select the products
manufactured by plants that have accumulated past results.
RE 3):
They are manufactured in Tochigi Prefecture, Ibaraki Prefecture, Gifu Prefecture,
Fukuoka Prefecture and in other prefectures and sold on a nationwide basis, but it is
necessary to initiate investigations to ensure that the required amount can be obtained.
RE 4):
Carbon dioxide is emitted owing to the use of heavy oil and electricity during the
calcination process. However, as calcination is carried out for recycled glass at a
relatively low temperature of between 900 and 1,000 degrees Celsius, as opposed to
178
temperatures of between 1,200 and 1,300 degrees Celsius for conventional tiles, a
reduction in the amount of carbon dioxide emissions is achieved during the
manufacturing process. An example of calculations6) on carbon dioxide emissions during
the manufacture of tiles that use glass foam aggregate indicates emissions of
approximately 160kg-CO2/ton, but the manufacture of tiles and blocks that use recycled
glass that has been crushed and calcinated may be considered to be below this amount.
Also, examples of the estimated carbon dioxide emissions from soil and rock during the
manufacture of ceramics (1995 Annual Report on Statistics for Ceramics and
Construction Material) indicate figures of approximately 5,850 kg-CO2/ton for plate
glass and 1,400 kg-CO2/ton for glass fiber products. Larger amounts of carbon dioxide
emissions are expected for recycled glass made from cullet from glass bottles.
Recycled glass tiles and blocks that have been subject to crushing and calcination are
melted at temperatures of approximately 1,000 degrees Celsius, so there is almost no
problem with regard to environmental safety. In case of using cullet as raw material, it
is important to improve quality by preventing contamination by foreign matters,
especially non-steel metals, ceramic, stone and impure glass (that exist in crystallized
glass, electric bulbs, fluorescent lighting and other heat-resistant kitchenware and
cooking utensils, etc.).
(2) Repeated Use
As there are no problems with regard to environmental safety, durability or other
factors, they may be used repeatedly if visual inspections show there is no damage to
the outside surfaces.
The cost of recycled glass tiles and blocks that have been subject to crushing and
calcination differs in accordance with size and type, but is approximately between
¥6,600 and ¥10,000 per square meter. The cost of ceramic floor tiles is between ¥7,000
and ¥10,000 per square meter, so the price of recycled products are almost the same.
(4) Necessity
The recycling rate for all types of glass is high at 90.3% (fiscal 2003.) The glass bottles
that can be recycled are restricted to colorless (white) and brown bottles, and as the
recycling of glass having other colors is difficult, it is mostly disposed of as waste
material. Glass cullet is mostly used as the raw material for the production of glass
bottles, but there are other uses for cullet, such as raw material of glass fiber, tiles,
179
blocks, road paving aggregate, lightweight aggregate and embankment filling, etc., and
usage in these areas was recorded at 150,000 tons in fiscal 20004).
[Products]
1) Crystal Clay (Crystal Clay Corp.)
2) Crystal Road (Kurosaki Harima Corporation)
3) Rega (TOTO LTD.)
[Reference]
1) Construction Research Institute: Handbook of Recycled Resources for Construction
Purposes, December 2000
2) Japan Association for Building Research Promotion: Survey on Evaluation Methods
for Construction Material that Reuses Waste Glass, March 1999
3) Kajima Corporation:
Eco-Crystal Clay catalogue
4) Glass Bottle Recycling Promotion Association: 2000 Annual Report
5) 1995 Annual Report on Statistics for Ceramics and Construction Material
6) Crystal Clay Corp. Homepage: Lightweight Ceramics that Reduce the Burden on the
Environment by Using G-Light Foam glass Aggregate, http://www.crystalclay.co.jp/
5.3. Fusion and Foaming
Foamed waste glass is a new lightweight material manufactured from glass
bottles. It is produced by crushing glass and mixing it with additives, and this mixture
is then inserted into a calcination kiln and heated to above the softening point of glass.
Foam glass has a very porous structure owing to very small gaps between
components, and is both lightweight and strong. This can be adjusted to an absolute dry
density of between 0.3 and 1.5 depending on the manufacturing condition, and it can
also be adjusted to a certain extent for moisture absorption at the same time. The
foaming process categorizes the end product into those with individual gaps and those
with continual gaps.
Hence, it is possible to produce products with different levels of moisture
absorption and absolute dry density depending on the size and number of the air
bubbles, which are adjusted with the type and amount of foaming additive that is used
during manufacture. It is also possible to obtain products with individual air bubbles
and continual air bubbles by regulating the temperature and continuity time when the
temperature is being raised.
180
Foam Glass Material
Earth Foundation Material
Reductions in earth pressure
- Lightweight backfill
Soil Improvement Material
Aggregate
Lightweight aggregate
Better compaction
of weak layers
Weight reducer
- Used in secondary
concrete products
- Material for drainage method
-Material for new earth foundations
- Mixture of raw limestone, soil
generated
during
construction,
various waste materials
Use with New Technology
-
-Water-retention material for
prooftop gardens
Architecture
Mixture for stability
processing
-Deep-layer mixture
processing (weak earth
foundations)
-Shallow-layer mixture
processing (road-bed soil)
Water-retention material
- Sound-proofing material,
heat-insulating of concrete walls
Rock bolting material
Contents
(Legend)
Vegetation-planting technology
- Vegetation planting on slopes
- Vegetation planting on bedrock
Contents
Symbol
Individual gaps
Continual gaps
Fig.5.3-1. Uses of Foam glass2)
Manufacturing Method1)
The manufacturing procedure for foam glass made from glass bottles is explained
below (refer to Fig.5.3-2.)
(1) Glass bottles collected.
(2) All metals and other impurities removed.
(3) Crushed into pieces of 4cm or less, and stored in a hopper.
(4) Crushed again into fine powder with a mesh of 30 or less, and stored once again
in a hopper. Additives (silicone carbide, or the like, with a mass ratio of 1.5%) are added
and mixed in.
(5) The mixture is heated, melted and foamed. Foaming occurs during the
solubilization process to produce an end product with an absolute dry density of
between 0.4 and 0.5 (g/cm3).
(6) The mixture is cooled (slowly-cooled.)
(7) The product is graded, and particle size of 95% or more of the end-product must
have a diameter of between 2mm and 75mm.
181
Fig.5-3-2. Manufacturing Process of Foam Glass
There are various kinds of foam glass products. Of them, the physical properties of glass
products containing individual air bubbles with an absolute dry density of between 0.4
and 0.5 (g/cm3) are shown in Table 5.3-1. The physical properties of continual air
bubbles differ depending on the size and quantity of the air bubbles. In particular, the
moisture absorption rates are large, and data that shows approximately 135%
absorption rates have been achieved in absorption test results3). Slaking rates are
approximately 0.1%, the repeated dry/moist absorption rates are 0.4%/time, and the
percentage of sodium sulfate weight loss is 3.7%. There is hardly any loss of foamed
waste glass, and stability levels are high. In the crushing rate tests, crushing rates of
30.9% were achieved during an upper load of 1,960kN/m2, which is high in comparison
with the values achieved with generally usedl crushed rock (5% to 10%). There are no
practical problems with regards to the use of foam glass as lightweight ground material,
backfill material or backing material, and it remains stable under loads in the long
term.
182
Table 5.3-1. Example of the Physical Properties of Foamed Waste Glass1), 6)
Item
Property Values
Absolute
dry
0.4 to 0.5
density (g/cm3)
Particle diameter
2 to 75 mm
range
Water content
0%
Singular
Unconfined
compression
3 to 4 N/mm2
strength
Moisture
30% or less
absorption rates
Density (g/cm3)
0.3 to 0.4 t/m3
Shearing
φ＝30° or less
During
resistance angle
Compaction CBR value
17.7%
Permeability
3×10-2 to 1 x 100 cm/sec
coefficient
pH
8 to 10
Slaking rates
Approximately 0.1%
Repeated
dry/moist
0.4%/time
moisture
absorption rates
Miscellaneous
Weight
lost
during
sodium
Approximately 3.7%
sulfate tests
Upper load 1,960kN/m2: 30.9%
Crushing rates
Upper load
980kN/m2: 10.5%
Upper load
490kN/m2: 2.6%
Fig.5.3-3. Photograph of Foam Glass Particles1)
183
Fig.5.3-4. Example of the Range of Particle Diameter for Foam Glass1)
The chemical properties of foam glass are shown in Table 5.3-2. As foam glass is made
by melting, foaming and solidifying used glass, it is chemically stable, and is also
characteristically strong at restricting the effects of heat, oil and chemicals. An example
of the results of effluent tests are shown in Table 5.3-3. The elution of toxic substances
is below the environmental standard values, so the safety levels for the surrounding
environment are high.
Table 5.3-2. Example of the Chemical Properties of Foamed Waste Glass4)
(wt%)
ig.Loss
SiO2
Al2O3
Fe2O3
MgO
CaO
Na2O
K2O
SO3
1.3
68.2
6.3
0.6
0.6
9.5
11.7
1.3
0.0
Table 5.3-3. Results of Effluent Tests on Foam glass1)
Item
Effluent Test Values
Environmental
(mg/L)
Standard Values (mg/L)
Cadmium
0.001 or less
0.01 or less
Lead
0.01 or less
0.01 or less
Hexavalen chromium
0.02
0.05 or less
Arsenic
0.01 or less
0.01 or less
Total mercury
0.0005 or less
0.0005 or less
Selenium
0.005 or less
0.01 or less
Fluorine
−
0.8 or less
Boron
−
1 or less
* The effluent tests were implemented in accordance with the
measurement methods provided in the separate table of the Environmental
184
Quality Standards for Soil Pollution (Ordinance No.46 enacted by the
Ministry of Environment on August 23rd, 1991.)
[Reference]
1) Kishimoto International Technology Research Center: Super Sol, Lightweight
Ground Material Made from Glass Bottles, Report on Public Works Materials Technical
Inspection Certification (Technical Inspection Verification No. 1103), Public Works
Research Center, August 1999
2) Mami Yokoo, Yu Hara, Katsutada Onizuka, and Isao Yasuda: Recycling Waste
Glass—Fundamental Characteristics of Foamed waste glass, 10th Symposium of the
Japan Society of Waste Management Experts Thesis Collection, pages 442 to 444, 1999
3) Clean Japan Center: Information on Waste Recycling Technology, Revised Edition on
Industrial Waste, pages 231 to 232, March 2001
4) Yu Hara, Katsutada Onizuka, Mami Yokoo, and Setsuko Momosaki: Slope
Vegetation on with the Use of Foamed waste glass, Soil and Foundations, Japanese
Geotechnical Society, Vol.47, No.10, pages 35 to 37, 1999
(5) Kohei Watanabe, Yasuharu Kamikawa, Jun Yano, and Yu Tomono: Characteristics
of Foam Glass Produced from Waste Glass, 10th Symposium of the Japan Society of
Waste Management Experts Thesis Collection, pages 439 to 441, 1999
185
5.3.1. Embankment Fill Materials
This section applies to the use of foam glass alone as lightweight embankment fill.
Foamed waste glass means glass made from glass bottles collected from domestic
households and the glass bottles collected from business waste by solubilizing,
solidifying, and mixing
with additives and then foaming at high temperatures.
[Description]
In addition to being used as backfill, filler and other forms of embankment fill,
foam glass can be used in a wide range of different applications, including
water-retention material for vegetation planting, spring water processing material, soil
improvement material, lightweight aggregate and public works material. Of these
different fields, this manual will concentrate on its use as lightweight embankment fill.
Foam glass can be used as embankment fill, filler for the rear surfaces of
retaining walls, and lightweight embankment fill and backfill for box culverts, and the
like for parks, greenbelt areas and leisure facilities (see Fig.5.3.1-1).
Fig. 5.3.1-1
186
(2) Evaluation Methods
(1) Foamed waste glass must be clean, hard and durable and must not contain
waste, sludge, thin shards of rocks, long shards of rocks or any other organic impurities.
(2) Foamed waste glass that is used as lightweight embankment fill must satisfy
the quality conditions such as particle size, absolute dry density and moisture
absorption rates listed in Table 5.3.1-1.
Table 5.3.1-1. Standards for Foamed waste glass Used as Embankment Fill
Inspection
Standard Value
Test Method
Item
Particle Size
Maximum particle
Conforms to JIS A 1204
diameter 75mm
Absolute Dry
Density
0.4 to 0.5 (g/cm3)
Moisture
Absorption
30% or less
Rates
(3) Quality inspections for foam glass products are to be implemented for each lot.
The size of each lot is to be determined through discussions with all related parties. Test
sampling is to be carried out in accordance with the sample extraction method
stipulated with JIS Z 9001, and suitable products must satisfy the standards listed in
Table 5.3.1-1. The purchaser must confirm the performance levels by the test result
charts submitted by the manufacturer.
for solubilized and foamed waste glass must conform to the stipulations laid down in
1.1.1 (2) 2), Chapter 2. In other words, effluent tests and toxic content tests on six
substances must be implemented, and the measured effluent amounts for the specified
toxic substances must be below the environmental standards.
[Description]
Re: 1): Foamed waste glass products must be free of waste, sludge and organic
187
impurities, must be clean, hard and difficult to break, and must not change its shape.
The quality levels required of foamed waste glass used as lightweight
embankment fill are listed in Table 5.3.1-1.
Re: 2)
(1) Environmental Safety Standards
Effluent tests and toxic content tests must be implemented on foamed waste glass to
confirm environmental safety levels when it is to be used as a recycled material.
Environmental safety standards must conform to the stipulations laid down in 1.1.1 (2)
2) (1), Chapter2. Foreign matters adhering to the glass bottles may affect the results of
the environmental safety tests.
(2) Effluent Test Methods
To conform to the stipulations laid down in 1.1.1 (2) 2) (2), Chapter 2.
The manufacturers of foamed waste glass products must implement tests to verify that
the material satisfies the environmental safety standards, and the purchaser must
check the environmental safety levels with the use of a test result chart or the like. It is
also advisable to carry out sample inspections when necessary. Tests are to be
implemented for each lot, and the size of each lot is to be determined through
discussions by all related parties.
(3) Technology Used
1) Design
Although it is advisable to use foam glass above the groundwater level, if it is to be
used below the groundwater level, tests must be carried out on buoyancy to see if it
floats, and all required levels of safety must be met. Moreover, purpose of use and
conditions of the groundwater at the construction site must also be fully understood and
stable calculations must be carried out by setting appropriate design constants.
2) Construction
(1) As foamed waste glass has the tendency to be crushed when rolling is carried out
with heavy machinery, it is necessary to observe full precautions in the selection of the
rolling machinery and the number of times to roll.
(2) Construction standards call for an even layer with a thickness of 30cm for a lift,
and rolling is to be performed with a 10-ton swamp bulldozer or 1-ton vibration roller.
(3) Compaction density must have an absolute dry density of 0.3t/m3 or more.
(4) In order to prevent separation of materials and earth and sand from becoming
mixed in the gaps in compacted foamed waste glass, it is advisable to lay a
188
water-permeable sheet along the area where the foam glass and the soil meet.
(5) The construction method must conform to ordinary public works construction
standards.
3) Maintaining Journals
The packaging or bags in which foamed waste glass products are wrapped must clearly
state that the contents are recycled materials, and it is necessary to maintain all design
diagrams and other construction journals. Foamed waste glass that has been dug up or
excavated has excellent levels of repeated durability, so it can be recycled in the same
way as similar types of lightweight embankment filling or backfill.
[Description]
Re: 1)
(1) Stability checking on surfacing due to buoyancy of the foamed waste glass.
It is necessary to check stability of the foamed waste glass to surfacing if there exists
possibility of the foamed waste glass being used under groundwater level or the foamed
waste glass being sunk under groundwater because of the change in water level. In
such cases, maximum water level is to be used as groundwater. Also, to remain on the
safe side, as the unit volume of foamed waste glass, one for the dry condition is to be
selected even when it is to be used under the surface groundwater, and the friction
forces with the earth foundation are to be ignored. If the safety levels with regard to
buoyancy are not satisfied, it is necessary to raise the formation level of the foamed
waste glass and to establish methods such as reducing the buoyancy that works on the
foamed waste glass, securing sufficient thickness of cover-soil and increasing the levels
of pressure load.
189
The safety levels F of foamed waste glass with regard to surfacing by buoyancy are
acquired with the following equation.
F = P/U
= (γｔｌ・ｈｌ＋γｔｓ・ｈｓ）／ρｗ・ｈｗ≧1.2
At this point, P: Pressure load (kN／ｍ2)
U: Buoyancy (kN/ｍ2)
γｔｌ: Unit mass of cover soil (t/ｍ3)
ｈｌ: Soil-cover thickness (m)
γｔｓ: Unit mass of foamed waste glass when dry (t/ｍ3)
ｈｓ: Formation level of foamed waste glass (m)
ρｗ: Unit mass of the water 1.0 (t/ｍ3)
ｈｗ: Thickness of the foamed waste glass beneath the groundwater level
(m)
(2) Stability checking on foamed waste glass with regard to cover soil load.
In order to secure long-term stability of foamed waste glass, it is necessary to establish
a compaction density (ρｄ) with which permissible bearing value (ｑa) becomes greater
than the load (cover soil load, p) applied to the foam glass.
ｑa≧ｐ = 9.8・γｔｌ・ｈｌ
At this point, ｑa: Permissible bearing value of the foamed waste glass (kN/ｍ2)
ｐ: Load applied to the foamed waste glass (kN/ｍ2)
(3) Design constants used in stability calculations
When foamed waste glass is used as lightweight embankment fill, the breakdown into
fine powder is advanced in accordance with the increased amount of rolling that is
carried out, and this results in not only increased density, it also leads to fluctuations in
strength characteristics and bearing value. Density is also increased when foam glass is
used beneath the groundwater level owing to the effects of water absorption. It is
therefore necessary to give full consideration to the groundwater conditions, etc., with
regard to the objectives of usage and the location of construction of foamed waste glass
in the design stages, and establish appropriate design constants accordingly.
An example of the design constants for foamed waste glass used as lightweight
embankment fill in standard construction (lift: 30cm, rolling machine: 1-ton vibration
190
roller or 10-ton swamp bulldozer, rolling count: N = 2 to 4 times) is shown in Table
5.3.1-2.
Table 5.3.1-2. Design Constants for Foamed Waste Glass Used as Lightweight
Embankment Fill
Compactio
n Density
(Dry
Density)
ρｄ(t／m3)
Yardstick for Rolling
Design Constants
*1Moist
Densit
y
ρｔ(t
／m3)
0.25
0.40
0.30
0.45
0.35
0.55
*2Adhesiv
*2Shearing
e Force
Resistan
ｃｄ(kN／
ce Angle
m 2)
φｄ(°)
*3Permissibl
30cm N (times/layer)*4
e
Bearing
10-ton
1-ton
value
Moist-eart
Vibratio
ｑa(kN／m2)
h Bulldozer
n Roller
39
0
0
98
2
4
137
4
(8)*5
25
0
Count When Lift =
30
*1: Values when used beneath the groundwater level(depth less than 3m.) Set in accordance
with the results of the immersion test. However, to discuss the stability to surfacing of
foamed waste glass, values in dry conditions in the above table are to be used to obtain safe
side values. A maximum water depth of 3m is applicable as a basic rule, but if the actual
depth exceeds this amount, it is necessary to set the value based on the results of another
immersion tests.
*2: Values established in accordance with tri-axial compression tests with water immersion
and non-immersion conditions.
*3: Values established in accordance with the test results of flat-slab load tests and the
results of calculations using the bearing value equation.
*4: Values acquired from the results of on-site rolling tests. The compaction density of ρｄ =
0.25 t/m3 is the value acquired when a lift is laid with compaction machinery.
*5: A compaction density ofρｄ = 0.33 t/m3 was acquired when rolling was carried out eight
times with a 1-ton vibration roller.
Re: 2):
(1) As foamed waste glass is light, it has superior handling easiness and safety levels
and the foamed waste glass also enables forming ground foundation having sufficient
bearing value and strength through simple rolling and compression. It also has good
permeability and water drainage capabilities, and construction work will not be
hindered by rainfall unless it rains much.
On the other hand, as foamed waste glass is easily crushed by heavy machinery when
rolled, it is necessary to give full consideration to the selection of heavy rolling machines
and the number of times rolling is to be carried out.
(2) In order to extract the predetermined levels of performance expected during the
design stage of foamed waste glass, in the construction, it is necessary to determine the
191
method of construction (layer thickness of lift, rolling machinery, rolling count) and
institute effective rolling management. When a lift with a thickness of 30cm are to be
laid and rolling is to be carried out with a 10-ten swamp bulldozer or 1-ton vibration
roller, the constants shown in Table 5.3.1-2 must be used for the machinery, the rolling
count and the design.
(3) The strength characteristics or the like of foamed waste glass fluctuate depending on
the compaction density. Relationship between compaction density ( ρ ｄ ) and the
shearing resistance angle (φｄ) is shown in Fig.5.3.1-2 as an example. According to this
example, it is necessary to establish a compaction density ρｄ of 0.3 t/m3 or more in
order to gain a shearing resistance angle φｄ of 30 degrees or more. This means that
foamed waste glass must be well compacted in order to achieve a standard compaction
density value of 0.3 t/m3 or more.
(4) When the foamed waste glass is used as embankment on the sot ground or cover soil
is applied over the embankment of foamed waste glass, for the purpose of preventing
the separation of the materials and incorporation of soil into the gaps of the foamed
waste glass, it is necessary to lay permeable sheets on the boundaries between foamed
waste glass and ground. It is also necessary to lay a waterproof sheet to prevent
rainwater from soaking into the foamed waste glass even when it is only being laid
temporarily.
Some views of an construction example using foamed molten glass as backfill on the
upper part of a box culvert are shown in Fig.5.3.1-3.
Fig.5.3.1-2. Example of the Relationship between Compaction Density (ρｄ) and the
Shearing Resistance Angle (φｄ)1)
192
(1) Transported and Delivered by Truck
(3) Foamed molten glass being laid
(2) Foamed molten glass is poured
(4) Rolling of foamed molten glass
Fig.5.3.1-3. Foamed Molten Glass Being Used as Backfill on the Upper
Part of a Box Culvert1)
Re: 2): The packaging or bags in which foamed molten waste glass products are
wrapped must clearly state that the contents are recycled materials. It is also necessary
to maintain all design diagrams and other construction journals to clarify the fact that
the product contains recycled material. Foamed molten waste glass has excellent
durability levels, and it is possible to use it repeatedly.
As the performance of foamed molten waste glass differs depending on the type and
volume of the additives and foaming material used, the manufacturing facilities and the
management method, it is necessary to use products that have been confirmed as
having high levels of quality, or products that have been awarded construction
technology inspection certification.
2) Results of Usage
193
There are many results of usage in both the private sector and public sector, and it is
necessary to select products manufactured by plants that have accumulated past
results.
3) Supply
The product is sold on a nationwide basis, but it is necessary to initiate
investigations to ensure that the required amount of product can be obtained.
The emission of carbon dioxide during the manufacturing process is reduced by
employing low-temperature solubilization or the like.
However, a certain amount of
carbon dioxide is generated through the use of fuel during the melting process.
[Description]
RE 1):
There are two types of foamed molten waste glass available depending on the foaming
conditions: material with individual gaps and material with continual gaps. Only
products with individual gaps, which have low water-absorption levels, can be used as
lightweight embankment fill or backfill. Foamed waste glass is a chemically stable
non-organic mineral, and it has high levels of resistance against heat, chemicals and oil,
etc. It may therefore be considered stable for supporting loads for long periods of time
when it is used as lightweight embankment fill, backfill or filling.
The level of foaming in foam glass differs depending on the type and volume of additives
and foaming material used, and the moisture-absorption levels and dry density differ. It
is therefore necessary to confirm that the product to be used satisfies the required
performance levels before use.
RE 2):
A survey carried out by the Public Works Research Institute (December 2002) indicated
only one report of foam glass being used as filling for the rear surface of a retaining wall,
and one report of it being used as embankment fill for a road, making a total of two
actual results. According to documentation maintained in the private sectors, a total of
fourteen examples of usage were recorded up until July 2002.
RE 3):
Factories that produce foamed waste glass are located in Gunma Prefecture, Tokushima
Prefecture, Saga Prefecture, Fukuoka Prefecture and Okinawa Prefecture, etc., and it is
sold on a nationwide basis. However, it is necessary to initiate investigations to ensure
that the required amount can be obtained. Moreover, not only production facilities, but
also acquiring a stable supply of used glass bottles that can be used as the raw
materials for foam glass will be a problem.
194
RE 4):
As heavy oil, electrical power and other forms of energy are used in the melting process,
carbon dioxide is emitted.
Although no data exists to provide detailed estimates of carbon dioxide emissions,
example7) for tile products indicates emissions of approximately 160kg-CO2/ton, and it
is estimated that the amount of emissions produced during the manufacture of foamed
molten waste glass is smaller than this amount. Also, in accordance with the
estimations of carbon dioxide emissions for soil and rock in the ceramic industry (1995
Annual Report on Statistics for Ceramics and Construction Material) emissions total
approximately 5,850 kg-CO2/ton for plate glass and approximately 1,400 kg-CO2/ton for
glass fiber products.
Foamed molten waste glass is melted at a temperature of approximately 900 degrees
Celsius, so it has high levels of environmental safety. However, there is a risk of glass
other than glass bottles being included in the raw material (crystallized glass, such as
heat-resistant kitchenware and cookery utensils, light bulbs, fluorescent lighting, etc.)
so it is necessary for the purchaser to confirm the results of tests on environmental
safety.
(2) Repeated Use
As indicated in 4.3. (2), Chapter 2, foamed molten waste glass that has been dug up or
excavated maintains sufficient durability for reuse, and it can therefore be recycled for
use as embankment fill, backfill and filling material. As mentioned above, foamed waste
glass that has been used in embankments is separated from earth and sand by a
permeable sheet, so it can be recycled if it is excavated independently and without
contamination. If, on the other hand, it has become mixed with soil, then it is possible to
handle it as mixed soil.
The price of foamed molten waste glass is approximately between ¥13,500 and ¥16,500
per square meter, which is cheaper than conventional organic lightweight embankment
fill when compared only against the unit cost.
(7) Necessity
The recycling rate for all types of glass is high at 90.3% (fiscal 2003.) The glass bottles
that can be recycled are restricted to colorless (white) and brown bottles, and as the
recycling of glass having other colors is difficult, it is mostly disposed of as waste
195
material. In addition to these glass bottles, hardly any of the waste window glass
generated during the dismantling of buildings is recycled. It is therefore necessary for
the waste window glass to be used as a construction material.
[Product Examples]
1) Super Sol (Super Sol Association)
2) Miracle Sol (Miracle Sol Association)
1) Kishimoto International Technology Research Center: Super Sol Lightweight Ground
Material Made from Glass Bottles, Report on Public Works Materials Technical
Inspection Certification (Technical Inspection Verification No. 1103), Public Works
Research Center, August 1999
2) Jin Mizutani, Yu Abe, Eizo Fukazawa, et al.: Engineering Characteristics and the
On-Site Application of Lightweight Ground Material Made from Foam Glass, Japanese
Geotechnical Society, Symposium for the Development and Use of Lightweight Earth
Foundation Material, May, 2000
3) Mami Sato, Katsutada Onizuka, Yu Hara, Atsuyoshi Eguchi: Recycling Waste
Glass—Construction Method of Lightweight Embankment Fill that Uses Foamed
Waste Glass, Japan Society of Waste Management Experts, 11th Symposium of the
Japan Society of Waste Management Experts Thesis Collection I, pages 486 to 488,
2000
4)
Yu
Hara,
Katsutada
Onizuka,
Mami
Sato,
and
Setsuko
Momosaki:
Environmentally-Friendly Examples of Vegetation Construction on Slopes—Vegetation
Construction Using Foamed Waste Glass, Japanese Geotechnical Society, Soil and
Foundations, Vol.49, No.10, pages 13 to 15, 2001
5) Katsutada Onizuka, Mami Yokoo, Yu Hara, and Shigeki Yoshitake: Example of the
Engineering Characteristics and Effective Use of Foamed Waste Glass, Japanese
Geotechnical Society, Soil and Foundations, Vol.47, No.4, pages 19 to 22, 1999
Purposes, December 2000
7) Crystal Clay Corp. Homepage: Lightweight Ceramics that Reduce the Burden on the
Environment by Using G-Light Foam glass Aggregate, http://www.crystalclay.co.jp/
196
Chapter Three. Test Construction Manual
197
Overview of Waste
Same as previously explained in 1, Chapter 2.
1.1. Sintering and Calcination Solidification Processing
The sintering solidification process is one where clay or other additives are
mixed with incineration ash or fly ash and incinerated in a sintering furnace at a
temperature of between 1,050 degrees Celsius and 1,200 degrees Celsius until the
mixture becomes solid. This is then crushed and graded to produce recycled incineration
ash aggregate.
The calcination solidification processing is where the above solid matter that
has been crushed and graded is added to glass powder or other additives, molded into
specific shapes, and then incinerated in a calcination furnace at a temperature of 1,100
degrees Celsius to solidify it into ceramic blocks.
Although the sintering and calcination processing is carried out at lower
temperatures than the solubilization and solidification processing, which require
temperatures exceeding 1,200 degrees Celsius, the solid particles are still able to fuse
together at this temperature and this leads to solids with greater strength owing to the
levels of compression, elaborateness and re-crystallization that are achieved as a result.
The procedure for manufacturing solid sintered and calcinated matter is shown in Fig.
1.1-1.
Fly Ash
Demineralization
Incinerated Ash
Additives
Impurity Removal
Process, Gas Exhaust
Process
(Demineralization Furnace)
Mixing, Particle Forming (Sintering Furnace)
and Sintering Processes
198
Crushing
and
Calcination
Grading
Binder
Processes
Mixing
Recycled Incineration Ash Subgrade Material
and
Molding Processes
Calcination
(Calcination Furnace)
Process
Recycled Calcinated Interlocking Blocks
Fig. 1.1-1. Manufacturing Procedure for the Sintering and Calcination
Solidification Processes
Note that the amount of sintering and calcination solidification processed
matter manufactured by an incineration ash recycling facility in Funabashi City, Chiba
Prefecture for fiscal year 2000 amounted to 760 tons of recycled incineration ash
subgrade material, etc., and 4,700 square meters of recycled calcinated interlocking
blocks.
(1) Shapes and Dimensions
The shapes and dimensions are listed in Table 1.1-1.
Table 1.1-1. Shapes and Dimensions of Sintered Solids
Shape
Dimensions (mm)
Cylinder
Diameter: 10, Length: 20
Rectangular
Length: 85, Width: 85, Thickness: 60
An example of the physical properties of sintered solids is shown is Table 1.1-2.
Table 1.1-2. Physical Properties of Sintered Solids1)
Item
Measurement
Particle Density (surface dry
2.607 g/cm3
density)
Moisture Absorption Rates
0.13%
Compression Strength
1,660 kgf/cm２
199
An example of the results of effluent tests on incinerated ash sintered solids is
shown in Table 1.1-3.
Table 1.1-3. Effluent Test2)
Item
Unit
Granulated
Non-Crushed Environment
Products
Products
al
Standard
Values*
Alkyl
mg/l
< 0.0005
< 0.0005
< 0.0005
< 0.0005
* < 0.0005
< 0.001
< 0.001
* < 0.01
< 0.01
< 0.01
* < 0.01
< 0.005
< 0.005
Mercury
mg/l
Total
Mercury
mg/l
Cd
mg/l
Pb
mg/l
Organic
< 0.01
* < 0.05
0.03
< 0.005
* < 0.01
Phosphorou
mg/l
< 0.005
< 0.03
s
mg/l
< 0.03
< 0.0005
mg/l
< 0.008
mg/l
Cr６＋
mg/l
As
CN
< 0.0005
< 0.002
< 0.008
mg/l
5.3
200
< 0.01
mg/l
< 0.002
< 0.01
mg/l
< 0.07
PCB
mg/l
< 0.001
Trichloroeth
mg/l
ylene
mg/l
Tetrachloro
14
8.8
(27 * < 0.01
deg. C)
−
ethylene
Cl
< 0.01
< 0.01
Cu
0.2
Zn
< 0.001
9.5 (27 deg.
F
C)
Se
pH
* The standard value stipulated in Reference Material 2. The same effluent
standards as those stipulated in Ordinance No.508 issued by the Environmental Health
Division, Health Service Bureau, Ministry of Health and Welfare.
(3) Physical Properties when Used as Subgrade Material
The physical properties of subgrade material made from crushed and graded
incineration ash sintered solids are shown in Table 1.1-4. The particle size conforms to
crusher-run (C-30).
Table 1.1-4. Physical Properties of Subgrade Material Made from Incineration
Ash Sintered Solids
201
Item
Surface
Dry
Moisture
Unit Volume
Absorption
Abrasion
Loss
Percentage
Revised
of Loss
CBR
Density
Measured
2.631
1.00 (%)
1.382 (kg/l)
16.1 (%)
7.5 (%)
44.7 (%)
Value
1.1.1. Subgrade Materials for Pavements
This section applies to the design and construction of roads using crushed and
graded calcinated and sintered solids made from general waste incineration ash
(hereinafter referred to as “recycled incineration ash subgrade material”).
Recycled incineration ash subgrade material used as paving subgrades must satisfy
the quality standards of the crusher-run stipulated in the Guidelines for Pavement
Design and Construction, etc. Test methods must conform to the methods stipulated in
the Guidelines for Pavement Test Methods.
The raw materials for recycled incineration ash subgrade material are incineration
ash or fly ash with which clay or other additives have been mixed. This mixture is then
solidified by incineration in a furnace at temperatures of between 1,050 degrees Celsius
and 1,200 degrees Celsius. The environmental safety standards and test methods for
recycled incineration ash subgrade material must therefore conform to the stipulations
laid down in 4.1.1 (2) (2), Chapter 2. In other words, effluent tests on 26 substances and
toxic content tests on nine substances must be carried out in order to guarantee quality
levels. However, if it can be confirmed that no problems exist with manufacturing
results and tests, then quality control based on the tests on six substances outlined in
1.1.1 (2) (2), Chapter 2 may be implemented.
The purchaser who intends to use recycled incineration ash subgrade material must
check the results of environmental safety tests implemented on a predetermined
number of lots and maintain and store records of the tests.
(3) Technology Used
1) Design
Recycled incineration ash subgrade material is considered to be equivalent to
crusher-run (C-30) with a revised CBR rating of 20% or more, and may be used in the
202
design of sub-base courses, or the like.
2) Construction
Recycled incineration ash subgrade material is to be used in the same manner as
crusher-run (C-30).
3) Maintaining Journals, Repeated Use and Disposal
When recycled incineration ash subgrade material is used in subgrades, the purchaser
must store the construction plan views, cross-sectional diagrams, quantity charts and
all other design-related documentation together with the test results of the recycled
incineration ash subgrade material, in consideration of future reuse and disposal of the
recycled material.
Recycled incineration ash subgrade material is sintered at a lower temperature than
molten slag, so it is necessary to periodically implement effluent tests on 26 substances
and toxic content tests on nine substances until it becomes clear that only tests on six
substances, which are carried out for molten slag, are applicable.
2) Usage Results
Results of using recycled incineration ash subgrade material are restricted to certain
areas, with the city of Funabashi in the Chiba Prefecture being the leading facility for
this.
3) Supply
The manufacture of recycled incineration ash subgrade material is limited to the city
of Funabashi in the Chiba Prefecture.
The amount of carbon dioxide emission during construction using recycled
incineration ash subgrade material is not greater than in construction using
conventional materials. However, as subgrade material is sintered and solidified at high
temperatures during the manufacturing process, the overall amount of carbon dioxide
emitted is higher.
[Examples of Usage]
Murata, Okamura and Murasawa: Guidelines of Recycling Incineration Ash Generated
from City Waste in Funabashi City and Technology to Use Recycled Materials
(proposed), April 1997
203
[References]
1) City of Funabashi: Technical Guidelines on Recycled Incineration Ash Material
(proposed), August 1998.
(proposed), March 1996.
3) Japan Waste Research Foundation: Research into the Appropriate Processing and
Effective Use of Incineration Ash, Fiscal 1996 Annual Report, March 1997.
4) Kanagawa Prefecture: Report on Surveys into the Effective Use of Incineration Ash,
March 1996
(proposed), August 1998.
204
2. Sewage Sludge
Overview of Waste
Same as previously explained in 2, Chapter 2.
2.1. Sintering and Calcination Solidification Processing
Sewage sludge incineration ash is the result of incinerating dehydrated sewage sludge
in a furnace at a temperature of approximately 800 degrees Celsius, which evaporates
all the moisture in the sludge and burns all organic matter, to leave an inorganic
residue. Depending on the type of coagulant that is added during the dehydration
process, the end product is categorized as either macromolecular sewage sludge
incineration ash or caustic lime sewage sludge incineration ash.
The following three methods are available for processing macromolecular sewage sludge
incineration ash.
(1) The macromolecular coagulant is added before dehydration and this mixture is then
dehydrated and incinerated to produce ash.
(2) Dehydration is carried out after thermal processing and this is then incinerated to
produce ash.
(3) Calcium hydroxide, iron chloride or a similar type of coagulant is added to the sludge
incineration ash manufactured with either method (1) or (2), and this is then added to
dehydrated sludge, mixed and incinerated.
This type of macromolecular sewage sludge incineration ash includes a silicon
compound (SO2) with a mass ratio of approximately 20% to 50%. This can be used as a
substitute for clay or the like that is used in manufacturing factory products such as
blocks, tiles, bricks, all of which are calcinated in the manufacturing procedure. When
this is used in calcinated factory-produced products, it is heated once again during the
manufacturing process to a temperature of between 1,000 degrees Celsius and 1,200
degrees Celsius in order to solidify it, and as this greatly reduces the risk of toxic
content elution: it is extremely effective for use as a construction material.
(2) Physiochemical Properties of Calcinated Ash
(1) Density
Density is related to the composition and chemical structure of the incineration ash and
macromolecular incineration ash generally has a lower density in comparison with
caustic lime incineration ash. This density becomes even lower if the incineration ash
contains non-combusted organic matter. The density of macromolecular sewage sludge
incineration ash is between approximately 2.5 to 3.0 g/cm3.
205
(2) Particle Size Distribution
Because the particle size of the calcinated ash affects the moldability, strength,
calcination temperature and compaction rates of calcinated products, in most cases it is
necessary to implement particulate adjustment by crushing, etc., before it can be used.
(3) Moisture Content
Moisture content must be measured in accordance with the methods stipulated in the
Sewage Examination Law. Examples of measurements of moisture content in ash that
is not affected by moisture, etc., immediately after incineration (hereinafter referred to
as “dry ash”) and in humidified ash, indicates that in most cases the moisture content of
dry ash is 0% and the moisture content of humidified ash between 30% and 40%. When
incineration ash is used in calcinated factory-produced products, moisture in the
incineration ash may cause problems, like cracking. It is especially necessary to keep a
close watch on products that have been molded with dry pressure, as these are easily
affected by moisture in the incineration ash.
(4) Ignition Loss
Ignition loss is the percentage of volume lost when dry and solid objects are heated to
temperatures of approximately 600 degrees Celsius. The tests for this must conform to
the stipulations laid down in the Sewage Examination Law.
The ignition loss of dry ash is about 1% or less. The larger the amount of ignition loss in
calcinated factory-produced products, the easier it is for these to form cracks or exhibit
other problems.
(5) Differential Thermal Analysis
Differential thermal analysis is a method of analysis that involves measuring thermal
behavior when the temperature of fuel is increased or decreased. This makes it possible
to estimate the physical and chemical changes that occur when incineration ash is being
calcinated. This is especially effective for controlling the calcination process.
(6) Thermal Expansion and Contraction Ratio
The thermal expansion and contraction ratio is an extremely important factor for
determining the level of contraction that is caused in the calcination process and the
temperature at which calcination should be carried out.
(7) Chemical Property Analysis
The chemical content of macromolecular sewage sludge incineration ash, which
contains silicon, calcium, or the like, affects the manufacturing process and the
performance of products, so it is advisable to perform a chemical analysis to discover the
actual components.
As an example of the composition of macromolecular sewage sludge incineration ash, it
206
contains approximately 20% to 50% silicon as SiO2, 10% or less calcium as CaO and
approximately 10% aluminum, iron and phosphorus as Al2O3, Fe2O3 and P2O5,
respectively.
(3) Physiochemical Characteristics
The physiochemical characteristics of macromolecular sewage sludge incineration ash
differ, depending on seasonal fluctuations that occur on the components of the
incineration ash and the operating conditions of the furnace used. It is therefore
advisable to have a good understanding of the fluctuation range of when using it as a
raw material for calcinated products.
In order to increase reliability levels of the product for its effective use, it is very
important to understand the fluctuation range and to implement quality control. Some
of the factors that lead to these fluctuations include changes in the quality of the sewage
collected at treatment plants, water treatment conditions and dehydration conditions,
the climate (especially the effects of rainwater,) the temperature of the furnace and the
various load conditions of the furnace.
(4) Environmental Safety Standards and Test Methods
Incineration ash is calcinated at a temperature of 800 degrees Celsius, so there is a
possibility that it will not pass environmental safety tests, depending on the condition of
the ash. As factory-produced products are incinerated for a second time at higher
temperatures, it is advisable to implement environmental safety tests based on
specimens obtained from factory-produced products.
2.1.1. Tiles and Other Calcinated Products
This section applies to tiles, bricks and other calcinated products that are made from
sewage sludge incineration ash, calcinated at a temperature of between 1,000 and 1,200
degrees Celsius. The calcination temperature of incineration ash is approximately 800
degrees Celsius, but heating it again to between 1,000 and 1,200 degrees Celsius during
the calcination process, reduces the possibility of toxic substances remaining.
Calcinated products can therefore be used as construction materials as long as
management policies for their environmental safety and physical properties are
implemented.
(1) Quality levels must satisfy the performance of products made with ordinary
materials, as stipulated by JIS or similar regulating body.
207
(2) The performance levels of sewage sludge incineration ash material are to be
determined by the manufacturer.
It is thought that the properties of calcinated products made from sewage sludge
incineration ash only need to satisfy the performance standards for ordinary products
as stipulated by JIS, or similar regulating body. The following standards exist for
calcinated products.
- Tiles: JIS A 5209
Incineration as is used for indoor tiles, external tiles, floor tiles, mosaic tiles, and so on.
Each of these products must satisfy the relevant standard values, etc., stipulated for
their intended usage.
An example of the procedure for manufacturing tiles that use incineration ash is shown
in Fig. 2.1.1-1.
[Pressure Molding Method]
Aggregate
Incineration Ash
Crus
Mixi
Calcinatio
Molding
n
Packaging
[Press-Molding Method]
Press-
Clay, etc.
Pressure
Drying
Calcinatio
Packaging
n
Molding
Fig. 2.1.1-1. Tile Manufacturing Procedure
Sewage sludge incineration ash is used for ceramic tiles that are used in the city of
Nagoya. The base materials for this are incineration ash and clay, with the percentage
of incineration ash mixed in at between 1% and 12%. These tiles are used in the
construction of sewage treatment-related facilities: on the external walls of the building,
as floor tiles in the main entrance and as wall tiles in the bathrooms.
- Ordinary Bricks: JIS R 1250
Sewage sludge incineration ash is categorized into Type-2, Type-3 and Type-4 when it is
used as material for ordinary bricks and each of these types must satisfy the relevant
standards stipulated for intended usage. It is also necessary to establish a manufacturing
method that matches the intended use of ordinary bricks. The city of Yokohama has
reported an example of incineration ash (mass ratio of 10%) being mixed with blended
clay and used as ordinary bricks.
- Tile Pipes: JIS R 1201
208
Examples exist of incineration ash being used in straight tile pipes and in branched tile
pipes. Manufacturers of tile pipes that utilize incineration ash must satisfy the relevant
standards stipulated for intended usage.
- Pedestrian Path Interlocking Bricks
These are not regulated by JIS, but examples of the required quality standards are
Table 2.1.1-1. Quality Standards for Interlocking Bricks
Item
Measurement
Standard
Moisture
Approximately
10 or less
Absorption Rates
0.16
Reference Standards
JIS R 1250 (Ordinary brick
Type-4)
(%)
Abrasion
Approximately
Resistance (g)
0.02
Bend Strength
Approximately
(N/mm2)
28
Compaction
Approximately
Strength (N/mm2)
105
Skid Resistance
Approximately
Coefficient (Wet)
68
0.1 or less
JIS R 5209
4.9 or more
Ordinary interlocking block
standards
29 or more
JIS R 1250 (Ordinary brick
Type-4)
40 or more
Manual for Design and
Construction of Asphalt
Pavement
A lightweight aggregate that uses sewage sludge incineration ash is being
manufactured in Tokyo and at other locations. The JIS stipulates the standards
(lightweight aggregate: JIS A 5002) for lightweight concrete aggregate that is used in
building construction. However, there is very little lightweight aggregate used in
cast-in-situ concrete and it is mostly used in the form of lightweight blocks for heat
insulating material, filler, or lightweight embankment fill.
(2) Environmental Safety Standards and Test Methods
The factory-produced products covered in this section are solidified by incinerating
them in furnaces at temperatures between 1,050 and 1,200 degrees Celsius. The
environmental safety standards and test methods must therefore conform to the
stipulations laid down in 1.1.1 (2) (2), Chapter 2.
(3) Technology Used
1) Design Method
Calcinated products that use sewage sludge incineration ash are to be used within the
range of the product specifications.
In the same way as ordinary products, calcinated factory-produced products that
209
contain sewage sludge incineration ash, must be used under conditions where load
pressures and environmental conditions do not exceed those stipulated. Also, products
with limited uses must not be used as replacements in locations where product
replacement is prohibited.
(1) It is necessary to verify that the required amount of product can be obtained.
(2) Consideration must be given to preventing the material from becoming mixed with
other ordinary materials.
(3) Construction methods must be the same as those using ordinary products.
Very few factory-produced products that use sewage sludge incineration ash are
manufactured and there are cases where distribution channels have not been
established, so it is necessary to ascertain that the required amount of product can be
obtained. There are also certain buildings for which the use of products, other than
ordinary product, is not permitted, so it is very important that this material is
completely separated from ordinary products to prevent them from becoming mixed.
The performance standards are the same for products containing calcination ash and
ordinary products, so construction may be carried out in the same way with both.
(3) Maintaining Journals
When calcinated products that contain sewage sludge incineration ash are used, records
that state this fact must be maintained. It is also necessary to accumulate information
on durability and other factors and to store this together with details on the location of
use, the manufacturer, the product name and other information per construction
records.
As factory-produced products that contain sewage sludge incineration ash are
calcinated at temperatures of between 1,000 and 1,200 degrees Celsius, they are not
thought to cause any problems regarding environmental safety. It is therefore
acceptable for the purchaser to confirm the results of effluent and toxic content tests on
six substances, in conformation with the stipulations laid down in Section Three, 1.1.1
(2) (2), Chapter 2. However, it is advisable for the manufacturer to implement effluent
tests on 26 substances and toxic content tests on nine substances, until it becomes clear
that six tests only are enough for safety confirmation.
As the manufacturer will select the quality and volume of sludge incineration ash that
is suitable for the manufacture of calcinated products, the purchaser needs only to
210
confirm that the performance levels satisfy the JIS standards, etc. When using products
for which JIS standards have not been stipulated, the purchaser must specify the
required performance levels, or agree to use products for which the performance levels
have already been specified by the manufacturer.
(3) Usage Results
There are quite a lot of results for cases in which sewage sludge incineration ash has
been used for factory-produced products, such as interlocking blocks, but hardly any
reports on long-term durability exist.
Examples of usage include flat slabs for pedestrian paths, tiles, bricks, permeable bricks
for pedestrian paths, water pipes, and the like.
(4) Repeated Use
There are many cases in which calcinated products that contain ordinary materials are
crushed and recycled for reuse as a material for calcinated products. It is thought that it
is possible to use this material repeatedly if an appropriate amount is mixed in with
new material, but no documentation regarding investigations into this exists.
As the amount of sewage sludge incineration ash that is mixed in is only approximately
10% of the base clay material, it has almost no effect on costs.
(6) Necessity
There are many applications outside of construction material for which sewage sludge
can be used and it is being used outside of the construction industry. As sewage sludge
is generated by public organizations in vast quantities, it is necessary to prepare for
large-scale use of this material in the construction industry. Mixing incineration ash that is without special processing - with other raw materials has the advantage of
reducing the financial burden on those who generate the sewage sludge.
As sewage sludge incineration ash is used in factory-produced products without any
special processing, it does not emit any more carbon dioxide than products that use
ordinary material. It therefore has an advantage compared to cases in which the sewage
sludge is converted to molten slag.
[Examples of Usage]
1) Example of surveys in tile manufacturing methods (Nagoya City).
2) Example of usage as interlocking bricks (Tokyo).
3) Example of usage as permeable bricks (Osaka Prefecture).
4) Example of surveys into tile pipe manufacturing conditions (Nagoya City).
211
5) Example of surveys into lightweight aggregate manufacturing conditions (Tokyo).
6) Example of usage as lightweight aggregate (Tokyo).
[References]
1) Association for the Use of Sludge Resources: Manual for the Use of Sewage Sludge
Construction Materials (proposed), 2001 Edition.
2.2. Lime Mixture Solidification of Incineration Ash
There are examples of sewage sludge incineration ash, without performing other
processing such as calcination, being mixed at a ratio of about 10% with lime-stabilized
or cement-stabilized soil and then used as backfill1). This method of usage is possible as
long as the condition of the sewage sludge incineration ash satisfies environmental
safety standards or as long as it’s condition after stabilization satisfies environmental
safety standards. However, the environmental safety standards and test methods
applied to the sewage sludge incineration ash used in this manner must conform to the
stipulations laid down in 3.1.2. (2) (2), Chapter 2. The purchaser is obliged to confirm
that the results of effluent tests on 26 substances and the toxic content tests on nine
substances for the incineration ash or stabilized material satisfy environmental
standards.
2.2.1. Soil Improvement Materials
This section applies to the use of sewage sludge incineration ash that has been mixed
with lime as soil improvement material or soil stabilization material.
The test and evaluation methods with regard to the physical properties of this
material are stipulated in Reference 1), (2), or similar regulations.
The environmental safety standards and test methods must conform to the
(3) Technology Used
The city of Nagoya implemented an investigation into a method in which between 0%
and 20% of raw lime was added to incineration ash and the end product used as soil
improvement material or soil stabilization material. The report on this indicates that
required strength levels were attained and that the results of effluent tests were
212
satisfactory1). Test constructions using this method were also carried out in the city of
Yokohama1).
A proposal for a manual on the use of sewage sludge incineration ash as soil
improvement material was also created.
[Examples of Usage]
1) 10% of lime-type incineration ash was added to residual construction soil, the
mixture used as backfill in a subgrade and a survey implemented after three years
confirmed that there was no problem with elution or strength (Yokohama).
2) Between 6% and 9% of macromolecular incineration ash and lime-type incineration
ash was added to backfill soil and a survey implemented three months after
construction confirmed that no problems had arisen (Nagoya).
This section applies to the use of sewage sludge incineration ash that has been mixed
with cement or lime as stabilizing subgrade material.
The test and evaluation methods with regard to the physical properties of this
material are stipulated in Reference (1), (3), or similar regulations.
(3) Technology Used
Examples of test pavement construction using subgrade material incineration ash - to
be used independently as subgrade material - have been recorded in the Saitama
Prefecture and the city of Yokohama. It has also been stated that incineration ash can
be used, even if it does not satisfy the standards required for subgrade material when it
is used independently, as long as it is stabilized with cement or lime1), 3).
[References]
1) Japan Sewage Works Association: Manual for the Use of Sewage Sludge Construction
Materials (proposed), 2001 Edition.
2) Ministry of Construction Public Works Research Institute: Manual for the Use of
Sewage Sludge Incineration Ash Soil Improvement Material, (proposed), November
1990.
3) Ministry of Construction Public Works Research Institute: 1988 Annual Report on
Research into Sewage Works, October 1989.
213
3. Coal Ash
Overview of Waste
The same as previously explained in 3, Chapter 2.
A new method of using coal ash, in which clinker ash is crushed down into fine particles
and used as fly ash is used, after controlling the particle size.
3.1.1. Filler for Asphalt Paving
This section applies to the use of crushed clinker ash as asphalt paving filler.
The quality standards for crushed clinker ash used as asphalt paving filler must
conform to the quality standards laid down in the Guidelines for Pavement Design and
Construction and the Pavement Construction Guidelines. The test methods for each
quality item stipulated in the quality standards must be carried out in accordance with
the methods stipulated in the Guidelines for Pavement Test Methods. When crushed
clinker ash is used as asphalt paving filler, it must be verified as conforming to the
details laid down in Table 3.1.1-1 and Table 3.1.1-2.
Table 3.1.1-1. Particle size (Source: Crushed Limestone Powder Particle Size Standards
Opening of Sieve
Passing
Volume
Percentage (%)
600µm
100
150µm
90 to 100
75µm
70 to 100
Table 3.1.1-2. Quality Standards (Source: Fly Ash, Limestone, Stone Dust Target
Values)
Item
Target Value
Plasticity Index (PI)
4 or less
Flow Test (%)
Moisture
50 or less
Absorption
4 or less
Expansion (%)
Peeling Test (%)
Pass
214
The environmental standards and test methods when crushed clinker ash is used as
asphalt paving filler must conform to the stipulations laid down in Section Two, 3.1.1 (2)
2), Chapter 2.
(3) Technology Used
(1) Design: Blend design for asphalt mixtures that use coal ash as filler must conform to
the methods and procedures stipulated in the Guidelines for Pavement Design and
Construction.
A point for consideration when designing the blend is that the density of coal ash is low,
so density adjustment must be carried out.
(2) Construction: Construction must basically conform to the stipulations laid down in
the Pacing Construction Guidelines. Results of the use of filler in asphalt pavement are
Table 3.1.1-3. Application Examples of Asphalt Filler
Location
Shimonosek Takehara
i
Domestic
Takehara
Shin-Ube
Isogo
Domestic
Domestic
Overseas
Domestic
Coal Ash
Coal Ash
Coal Ash
Coal Ash
n Type
City
Road Private
Road
Constructi Road
Constructio
on
of 1982.1
Overseas
Private
Town
Private
Road
Road
Road
Constructio Constructio Constructi Constructi
n
Date
ma
Coal Ash
Coal Ash
Constructio Private
Matsushi
1982.12
Constructio
n
n
on
on
1982.10 to
1983.3
1984.4 to 8 1985.12
Kagawa
Fukushim Okinawa
1983.1
n
Region
Hiroshima
Hiroshima
Hiroshima
a
When fly ash or crushed clinker ash is used as an asphalt pavement filler, the purchaser
must record and store all documents pertaining to the materials used (including the
results of tests on the fly ash and crushed clinker ash), construction diagrams, design
mix formula and all other documentation relating to the construction so that they can
be referred to when the material is to be used repeatedly or disposed of. The composition
215
of coal ash differs depending on the region in which it was produced, so it is necessary to
confirm that it satisfies the environmental standards for soil and the purchaser must
verify that it is suitable for use by checking the details of all design documentation.
(1) When using asphalt pavement filler it is necessary to consider the fact that in
comparison to stone powder, particles of coal ash are smaller and Marshall stability
tests indicate that the density is larger, the gap ratio smaller and the saturation level
larger, so the suitable amount of asphalt to be used is smaller than when stone powder
is used.
Owing to this, it is necessary to confirm the results of blending tests and mixture status
tests on the asphalt mixture (fatigue-resistance, flow-resistance, abrasion-resistance,
peel-resistance, etc.,) and initiate inspections into the quality standards.
(2) A point for consideration with regard to construction is the necessity to carry out an
investigation to make sure that the amount of coal ash required for the scale of the
project can be obtained and to make sure that storage space is available that will
maintain the required quality.
[References]
1) Japan Fly Ash Association: Coal Ash and Its Uses (Mainly as Road Materials), April
1987.
2) Japan Fly Ash Association: Report on Investigations into the Use of Coal Ash as Road
Paving Material, April 1989.
3) Japan Fly Ash Association: Technical Manual Relating to Coal Ash and Its Uses,
April 1987.
4) Japan Society of Civil Engineers: Current Situation and Perspectives on the
Technology for Using Coal Ash as Material in Public Works Projects—Improving
Landfills, Embankments and Ground Improvement, April 1990.
5) BVK Technical Documentation: A Granulate with many Possibilities (Steag).
6) Von K.-H. Puch, W. vom Berg: Nebenprodukte aus kohlebefeuerten Kraftwerken,
VGB-Kraftwerkstechnik, 1997, Helt 7.
3.2. Hydrothermal Solidification
Process Overview
216
Hydrothermal solidification is a method of steam-curing in which a solidification
reaction is promoted within a short period of time between the properties of coal ash
(CaO, SiO2, Al2O3, etc.) and limestone, in order to create solids with high levels of
strength. Although greater strength can be obtained with this method in comparison to
a solid cement mixture, it is more expensive to produce. Long-term stability with regard
to the elution of heavy metals is good, but it is necessary to carry out test chamber
measurements and on-site measurements thoroughly before a hydro thermal solid made
from coal ash is used as subgrade material for an asphalt pavement.
3.2.1. Asphalt Pavement
This section applies to the use of coal ash that has been subject to hydrothermal
solidification, in asphalt paving.
(1) Quality Standards
The quality standards for subgrade material that contains coal ash subjected to
hydrothermal solidification must conform to the relevant subgrade material quality
standards stipulated in the Technical Standards and Descriptions Related to the
Configuration of Pavement, the Guidelines for Pavement Design and Construction and
the Pavement Construction Guidelines, or the like in accordance with the type, location,
construction method and materials of the roadway paving.
Recycled subgrade material that has been adjusted to obtain the required quality
levels by mixing coal ash that has been subject to hydrothermal solidification together
with recycled asphalt concrete aggregate must conform to the quality standards
stipulated in the Technical Guidelines for Plant Recycled Pavement. A summary of
these quality standards are shown in Table 3.2.1-1 and Table 3.2.1-2.
Table 3.2.1-1. Quality Standards for Subbase course Material
Construction Method and Revised
Unconfined
Materials
Strength MPa (kgf/cm２)
Granulated
CBR %
subgrade 20 or more1)
Compression
−
PI
6 or less2)
material, crusher-run, etc.
Cement
stabilization
−
Material age 7 days, 1.0 (10)
−
−
Material age 10 days, 0.7 (7)4)
−
process3)
Lime stabilization process3)
217
1)
10 or more with simple paving.
2)
9 or less with simple paving.
3)
None with simple paving.
4)
0.5 with cement concrete paving.
5)
The prescribed particulate size is required for crusher-run. It is also advisable to
attain a PI (plasticity index) of 9 or less for cement and between 6 and 18 for lime when
stabilized aggregate has a revised CBR of 10% or more.
Table 3.2.1-2. Quality Standards for Subbase Course Material
Construction Method
Revised
and Materials
CBR %
Unconfined
Marshall
Other
Compression
Stability
Levels
Strength MPa Level
Size-controlled crushed
stone
Hot
(kgf/cm２))
−
or
80
Quality
kN
(kgf)
−
PI 4 or less
more1)
asphalt
−
−
stabilization process
3.43 (350)
Flow value 10 to
or more
40
Gap rate 3 to
Cement
stabilization
Material age 7
−
process
−
12%
−
−
−
days 2)
2.9 (30)
Lime
stabilization
Material age 7
−
process
days 3)
1.0 (10)
1)
60 or more with simple paving
2)
2.5 (25) with simple paving, and 2.0 (20) with cement concrete paving.
3)
0.7 (7) with simple paving.
The aggregate used as subbase course material must have an abrasion loss of 50% or
less. Prescribed particle sizes are required with size-controlled crushed stone. It is also
advisable for aggregate that is to be used in the stabilization process to have a revised
CBR 0f 20% or more (excluding asphalt,) a PI of 9 or less (6 to 18 for lime) and a
maximum particle diameter of 40mm or less.
(2) Quality Test Methods
The test methods for the quality items stipulated in the quality standards must
218
conform to the methods laid down in the Guidelines for Pavement Test Methods.
The environmental safety standards and test methods for coal ash that has been
subject to hydrothermal solidification must conform to the stipulations laid down in
3.1.1 (2) (2), Chapter 2.
(3) Technology Used
1) Design
The design of subgrade that contains coal ash subjected to hydrothermal solidification
must conform to the methods and procedures stipulated in the Guidelines for Pavement
Design and Construction, the Manual for Design and Construction of Asphalt Pavement
and Manual for Design and Construction of Concrete Pavement, and the Pavement
Construction Guidelines, etc. However, the unit weight and maximum dry density of
hydrothermal solidification material is generally about half of the values for
size-controlled crushed stone and it also has the characteristic of having greater levels
of moisture absorption. Moreover, the quality of the hydro thermal solidification
material differs, depending on the properties of coal ash materials and the
hydrothermal solidification methods. It is therefore advisable to use equality conversion
coefficients that correspond to the quality standards of subgrade material that contains
hydrothermal solidification material during the design stage. As mentioned above, the
results of usage are limited to granulated subgrade material and size-controlled
subgrade material used on roads with a design traffic volume of B or less, so it is
necessary to carry out test paving construction to confirm all aspects when it is to be
used in conditions other than this.
In order to guarantee safety, when subgrade material that contains coal ash subjected
to hydrothermal solidification is to be used in a location where the material is brought
into direct contact with acid water, it is necessary for the manufacturer of the
hydrothermal solidification material and the purchaser to discuss and agree on
changing the conditions of the effluent tests when necessary to confirm safety levels
beforehand.
2) Construction
Construction of subgrades that use coal ash subjected to hydrothermal solidification
must conform to the methods and procedures stipulated in the Guidelines for Pavement
Design and Construction and the Pavement Construction Guidelines, etc., depending on
219
the method of construction being used. The purchaser must confirm the details of all
effluent test results listed on the result check sheet for the tests carried out on subgrade
materials that use coal ash subjected to hydrothermal solidification and store this sheet
with all other construction records.
3) Repeated Use and Disposal
When subgrades that use coal ash subjected to hydrothermal solidification are
constructed, the purchaser must record and store plan views of the construction location,
cross-sectional diagrams, quantity charts and all other documents pertaining to the
construction and store them together with results of tests carried out on subgrade
materials that use coal ash subjected to hydrothermal solidification created by the
manufacturer thereof, so that they can be referred to when the subgrade material is to
be repeatedly used, or disposed of.
When subgrade materials that contain coal ash subjected to hydrothermal solidification
are to be recycled for reuse or disposed of, the purchaser must confirm the details of all
design records created at the time of original use and establish applicable methods and
procedures for the purpose of reuse or disposal.
Examples of the properties of subgrade materials that use coal ash subjected to
hydrothermal solidification are listed in Table 3.2.1-3.
Table 3.2.1-3. Properties of Subgrade Materials that Use Coal Ash Subjected to
Hydrothermal Solidification
220
Item
37.5
mm
31.5
19
Particle
4.75
size
2.36
0.425
0.075
Revised CBR
Plasticity Index
Abrasion Loss (%)
Percentage of Loss (%)
Apparent Density
Density
Surface Dry Density
(g/cm3)
Bulk Density
Unit weight (kg/l)
Moisture Absorption Rates (%)
Maximum Dry Density (g/cm3)
Optimal Water Content (%)
Examples
of
Standards Stipulated in
Measurements
of
the
Guidelines
for
Subgrade
Materials
Pavement Design and
that Use Coal Ash
Construction
and
Subjected
to
Pavement Construction
Hydrothermal
Guidelines
Solidification
100
100
99.4
95 to 100
87.5
60 to 90
32.7
30 to 65
23.1
20 to 50
8.2
10 to 30
2.4
2 to 10
105
80 or more
N.P.
4 or less
32.1
[50 or less]
83.7
[20 or less]
2.382
(2.672)
1.642
(2.621)
1.106
(2.59)
0.826
(1.79)
48.4
(1.20)
0.949
(2.240)
55.9
(6.6)
Note #1: Only the result of primary crushing is shown for Particle size.
Note: #2: In the right-hand column the particle size is M-30, the figures in the square
parenthesis [ ] are the target values, and the figures in the round parenthesis ( ) are
examples.
The unit weight and maximum dry density of coal ash subjected to hydrothermal
solidification is generally about half of the values for size-controlled crushed stone and
the moisture absorption rates are dramatically higher. The revised CBR and plasticity
index satisfy the standards for size-controlled crushed stone (M-30) stipulated in the
Manual for Design and Construction of Asphalt Pavement and, as it also has
hydraulicity, it is possible to use subgrade material made from coal ash subjected to
hydrothermal solidification as subbase course material.
[Examples of Usage]
Examples of usage are shown in Reference (1) and (2).
221
[References]
1) Isao Ishihara, Hidetoshi Izumi, Kazuo Amaraku and Shigenori Nagaoka: Practical
Use of Subgrade Material that Uses Coal Ash as its Raw Material, Road Construction,
Pages 43 to 48, September 1996.
2) Hidetoshi Izumi, Kozo Kuga and Koken Ozaki: Development of “Naruton”, a
Subgrade Material Recycled through Molding and Steam-Curing Coal Ash, Pavement,
Pages 15 to 19, November 2000.
3.3. Selected Use
The case where coal ash generated from coal thermal power plant or the like is selected
for use without being subjected to processing like solubilization, cement solidification,
calcinations, or the like, is described below.
The physical properties and chemical composition of coal ash is shown in Table 3.3.1.
Table 3.3-1. Physiochemical Properties of Coal Ash
Item
Coal
Ash Soil
Standards
(Mountain
Soil)
Particle Density
1.9 to 2.4
2.5 to 2.7
Sand Content (%)
0 to 10
―
Silt Content (%)
80 to 90
―
Clay Content (%)
10 to 20
―
Fluidity Limit
N.P.
―
Plasticity Limit
N.P.
―
SiO2
40 to 75
62.8
Al2O3
15 to 35
24.0
Chemical
FeO3
2 to 20
1.6
Composition
CaO
1 to 15
0.0
MgO
1 to 3
0.0
―
11.3
Particle
Composition
Consistency
ρs (g/cm3)
Others
222
The majority of coal ash is grayish-white in color. Reddish or blackish coal ash also
exists, depending on its components. Density is within a range of 1.9 to 2.4 g/cm3, giving
coal ash a smaller particle diameter than soil. Bulk density is between 0.8 and 1.0 g/cm3.
The particle distribution of the relatively rough clinker ash having particle sizes of
between 0.1mm to 1mm is 50%, while particles with a size of 1mm or more occupy 50%.
In the case of fly ash, particles with sizes of 0.1mm or less occupy 90%. Also, as the
shape of the particles are mostly spherical, it is not possible (N.P.) to measure the
fluidity limit and plasticity limit for consistency characteristics, which means that is
very close to the consistency of extremely fine sand.
The chemical composition of coal ash is very similar to mountain soil in that it mostly
consists of silica (SiO2) with high levels of pozzolanic reactivity, alumina (Al2O3) and
ferric oxide (FeO3). It also contains a small amount of calcium carbonate (CaO) and this
is the reason for its slight self-hardening properties. There are also cases where it
contains trace amounts of toxic heavy metals, such as total mercury, cadmium, lead,
arsenic and hexavalent chromium, depending on the region where it was produced.
The pH level of coal ash is approximately 11 and it has similar alkali properties to
cement. With regard to elution characteristics, there are also cases where traces of
heavy metals, such as hexavalent chromium, arsenic, or the like are detected in
volumes that exceed the environmental standards for soil. Boron especially, which was
newly added to the list of soil environment standards in 2001, often exceeds
environmental standards. According to a report entitled “Research and Development
into the Chemical and Mechanical Characteristics for the Rolling and Slurry
Construction of Fine Coal Powder Incineration Ash” (Report on Research Result,
Program supported by Grant-in-Aid for Development of Coal Production, Japan Coal
Energy Center, fiscal 2000,) the amount of boron elution reached 5- to 20-times more
than the amount stipulated in environmental standards for soil. It is therefore
necessary to implement effluent tests at the time of use. Examples of effluent test
results on coal ash are shown in Table 3.3-2.
223
Table 3.3-2. Effluent Test Results on Coal Ash (Examples)
Country
Item
Solve
nt
Pure
Japan
Coal
Alkyl
Total
Mercur
Mercu
y
ry
Cadmiu
Lea
m
d
Organic
Phosphor
us
(Unit: mg/l)
Hexavale
nt
Arseni
Chromiu
c
Cyanide
PCB
m
ND
ND
ND
ND
ND
0.19
ND
ND
ND
ND
ND
ND
ND
ND
0.19
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
0.10
ND
ND
ND
ND
ND
ND
ND
ND
0.15
ND
ND
ND
ND
ND
ND
ND
ND
ND
0. 06
ND
ND
ND
ND
ND
ND
ND
ND
0.2
ND
ND
≦
≦
≦
≦
≦
≦
≦
≦
0.005
0.3
0.3
1
1.5
0.3
1
0.00
Wate
r
Sea
Water
Pure
China
Coal
Wate
r
Sea
Water
Pure
South
Africa
Coal
Wate
r
Sea
Water
Pure
Australi
a Coal
Wate
r
Sea
Water
Judgment
Standards
for
ND
3
Landfill
Processing *
* Ministerial ordinance stipulating the judgment standards for industrial waste that contains heavy metals, etc.
(Ministerial Ordinance No.5, 1973, revised as Ministerial Ordinance No.1, 2000, general Administrative Agency of
the Cabinet)
[References]
1) Japan Electric Power Civil Engineering Association: Electric Power Civil
Engineering No.296, 2001.
224
2) Environmental Technology Association, Japan Fly Ash Association: Coal Ash
Handbook, Fiscal 2000 Edition.
3) Japan Coal Energy Center: Research and Development into the Chemical and
Mechanical Characteristics for the Rolling and Slurry Construction of Fine Coal Powder
Incineration Ash, Fiscal 2000.
3.3.1. Admixture Materials for Concrete
This section applies to the use of coal ash that has not been classified or subjected to
other processing as admixture for plain or reinforced concrete in vast amounts
(hereinafter referred to as “CA concrete”). The design mix formula of CA concrete is that
it is to be blended with as much coal ash as possible without losing the performance
levels that can be expected of concrete. However, as the particle content (coal ash and
cement content) is much larger than in conventional concrete, the characteristics in
construction are different from conventional concrete owing to the powder effect of coal
ash and pozzolanic reactivity. It is therefore necessary to carry out sufficient inspections
and tests when it is to be used in actual structures, to ensure that it can be evaluated in
accordance with the requirements of the relevant structure.
There are two types of coal ash available: clinker ash that falls to the bottom of boiler
furnaces and fly ash that is accumulated in dust collectors. More specifically, fly ash
before classification is called original powder and this original powder is classified into
two types of powder: fine powder and coarse powder. After classification the powder is
categorized as “fly ash” by JIS. The fly ash regulated by JIS is generally used as a
concrete admixture, but in this manual coal ash (original powder) that has not been
classified, is used for CA concrete. The results (examples) of coal ash measurements are
shown in Table 3.3.1-1. The quality levels of this satisfy the Type II category of
JIS-regulated fly ash. However, the quality of coal ash does not remain constant and
there is a possibility of fluctuation, so it is necessary to confirm quality levels prior to
usage.
Table 3.3.1-1. Examples of Coal Ash Quality Levels (Original powder)
Chemical Properties (%)
Coal Ash
Category
SiO2
AlO3
Fe2O
3
CaO
SO3
Ig.los
s
225
MB
Absorptio
n
(mg/g)
Densit
y
(g/cm3)
Specifi
c
Surfac
e Area
(cm2/g)
Average
Particle
Diamete
r
(µm)
A
B
C
D
E
Average
Standard
Deviatio
n
59.
3
57.
4
55.
6
56.
1
55.
4
56.
8
24.
7
27.
6
27.
4
32.
8
27.
6
28.
0
1.6
2
2.9
4
4.8
4.1
0.3
1.7
0.49
2.23
3210
16.4
4.8
4.7
0.3
2.9
0.55
2.23
3220
14.4
5.8
3.5
1.0
2.5
0.47
2.16
3130
21.3
3.9
4.1
0.4
1.6
0.24
2.18
3460
16.6
6.4
5.3
0.2
2.4
0.37
2.21
2710
22.9
5.1
4.3
0.4
2.2
0.42
2.20
3150
18.3
0.97
0.6
8
0.3
2
0.55
0.122
0.031
273
3.60
It has been confirmed that the basic characteristics of hardened CA concrete are
approximately the same as ordinary concrete. It is therefore acceptable to use the
standard test methods for ordinary concrete when testing the quality levels of CA
concrete.
(3) Technology Used
It is possible for fly ash to constitute a maximum of 30% of the concrete’s total mass with
the fly ash cement currently in the marketplace and it is mainly used as dam concrete,
etc., for the purpose of restraining heat generated by hydration of the concrete. However,
it has the disadvantage of having low strength in the initial stages. One of the methods
of overcoming this disadvantage of CA concrete, is to maintain a predetermined amount
of cement and replace a certain amount of the fine aggregate with fly ash. Although the
unit mass of water increases when fine particles are used in large quantities, this can be
avoided by using high-performance water reducing agents.
Although it is possible to manufacture CA concrete with an approximate surface
compaction strength of 60N/mm2 in laboratory tests, there are no results of it actually
being used in pre-stressed concrete or high-strength concrete structures, so it is
advisable to set the maximum specified concrete strength as approximately 30N/mm2 for
the design of CA concrete.
An example of a CA concrete design mixture formula is shown in Table 3.3.1-2. The
amount of unit mass of water is larger than in ordinary concrete, owing to increases in
unit mass of powder in CA concrete. This leads to the necessity of using a
high-performance AE water reducing agent, or the like, to prevent increases in water
and obtain the same levels of slump. The amount of additive to be used increases in
accordance with increases in the amount of unit mass of powder.
Moreover, the non-incinerated carbon that remains in coal ash absorbs AE adjustment
226
agents and consequently hinders air entrainment performance through the concrete. An
AE adjustment agent for the specific use of fly ash has been developed to counteract this
problem.
Table 3.3.1-2. Example of CA Concrete Blending
Concrete
Type
Water
Cement
Ratio W/C
(wt.%)
Water
Powder
Ratio
W/P
(wt.%)
Unit Weight (kg/m3)
W
C
CA
S
G
SP
AEA
60
30.0
180
300
300
433
1004
7.86
0.250
CA
65
32.5
180
277
277
478
1004
6.49
0.221
70
35.5
180
257
257
516
1004
5.31
0.194
Note (1): Blending Conditions = Slump: 18±2.5cm, Air: 4.5±1.0%
Note (2): C: Ordinary Portland cement, CA: Coal ash
S: Land sand (surface dry density: 2.59g/cm3, Moisture absorption: 1.52%,
Coarse particle ratio: 2.75, Solid content ratio: 68.2%)
G: Crushed stone 2005 (surface dry density: 2.64g/cm3, Moisture absorption:
0.59%, Coarse particle ratio: 6.66, Solid content ratio: 61.5%)
SP: Higher-performance AE water reducing agent (polycarboxylate system
oxychloride), AEA: Fly ash AE adjustment agent
In comparison with ordinary concrete, CA concrete generally has the following
characteristics:
a) When their water-cement ratio is same, breeding rates of the CA concrete are
remarkably lower than that of ordinary concrete. This is owing to the fact that the
percentage of powder that makes up the composition of the concrete is large, and
therefore the redundant water content is hardly exuded.
CA concrete has excellent resistance to separation of materials and this is effective in
preventing dilation that adversely affects the quality of centrifugally molded products.
b) With a water/cement ratio of 60%, 65% or 70%, the compaction strength of CA
concrete, when cured in accordance with standard procedures, is larger than in ordinary
concrete that has the same water/cement ratio. One of the reasons for the development
of strength is that the coal ash that is used instead of sand improves strength due to a
pozzolanic reaction.
c) The static elasticity coefficient has a tendency to be slightly lower than in ordinary
concrete, when the same compaction strength is applied. However, the static elasticity
coefficient of CA concrete that has a compaction strength within a range of up to
approximately 60N/mm2, is about the same as the value stipulated in the Japan Society
of Civil Engineers “Standard Specifications for Concrete”.
d) The relationship between compaction strength and tensile strength when compaction
strength is within a range of up to approximately 60N/mm2 is the same as ordinary
227
concrete. Moreover, the tensile strength of CA concrete is slightly larger than the value
used for designing ordinary concrete, which is stipulated in the Japan Society of Civil
Engineers “Standard Specifications for Concrete”.
e) There is very little difference between ordinary concrete and CA concrete, for the
amount of time required for coagulation when water-cement ratios and construction
temperature (and environmental temperature) are the same.
f) Increases in heat insulation temperatures are the same as in ordinary concrete, up to
approximately one day after the test construction. In the end, however, the amount of
temperature increase is greater than in ordinary concrete, even when the same unit
mass amount of cement is used. This is thought to be a result of a pozzolanic reactivity
generating heat due to the vast amount of coal ash used.
g) The results of tests that promote neutralization show the same or slightly lower
values than with ordinary concrete.
h) Drying shrinkage is less than in ordinary concrete, even when the unit weight of
water and unit mass amount of cement used are the same.
i) Freeze-thaw damage is the same as with ordinary concrete, if the water/cement ratio
is within a range of up to 70% and predetermined amounts of air can be passed through
it.
Construction with CA cement is carried out in accordance with the same methods used
for ordinary concrete. It is advisable that the instructions stipulated in the Japan
Society of Civil Engineers “Standard Specifications for Concrete” are observed for this,
as a basic principle. However, CA concrete containing vast amounts of coal ash per unit
volume (or powder per unit volume) may present obstacles to pump pressure
performance, surface finishing and other construction-related performance factors, due
to increased viscosity of the concrete. In this case, it is necessary to make adjustments
by increasing the water content or reducing the amount of fly ash in the admixture.
When coal ash is used in concrete structures, it is necessary to clearly mention this fact
in the blending charts and other construction records.
With regard to repeated usage, it is assumed that concrete recycled from dismantled
structures is used in concrete with extremely low strength requirements or only coarse
aggregate is removed to leave just the ordinary aggregate for reuse and therefore, there
should be no specific problems.
With regard to the elution of toxic matters, examples of effluent tests carried out on
hardened mortar that has been subject to wet screening, confirm that it satisfies the
228
stipulations laid down in the Environmental Quality Standards for Soil Pollution.
Although effluent tests are not implemented on construction material that are used as
hardened matter, such as concrete, it is advisable to carry out environmental safety
tests on either the fly ash or the concrete used in CA concrete. The environmental safety
standards and test methods are to conform to the descriptions already provided in 3.1.1
(2) 2), Chapter 2.
There are cases where coagulation time is extended by adding high-performance AE
water reducing agents in order to provide CA concrete with the required levels of
workability.
When the breeding volume is remarkably smaller than with ordinary concrete, it is
necessary to pay attention to duration of the period for finishing treatment and the
occurrence of cracks immediately after construction.
As CA concrete contains a large amount of powder components, it has higher levels of
viscosity than ordinary concrete. Although higher viscosity makes material slaking
more difficult, it also adversely affects the pumping of the concrete. It is therefore
important to confirm that conventional methods of construction are possible when using
blends for which there are few usage results.
(3) Usage Results
There are very few instances of CA concrete actually being used. It is therefore
advisable to choose ready-mixed concrete plants or manufacturing plants that are
equipped with special storage silos, high-performance water reducing agent tanks and
other required facilities, that have already accumulated results.
(4) Supply
Although there are no particular problems with obtaining coal ash, it is necessary to
investigate and ensure that the ready-mixed concrete plant is equipped with special
coal ash storage silos, high-performance water reducing agent tanks and the other
facilities for supplying the necessary amounts of CA concrete.
(5) Repeated Use
It is extremely difficult to extract only the coal ash from dismantled concrete structures.
There is no problem, however, if the used concrete already is turned into powder or
aggregate to be used in low-strength concrete. However, it is advisable to make sure
that it is capable of providing the required levels of performance.
Even if the objective of using coal ash in vast quantities is attained, the cost of
manufacturing the concrete is increased due to the usage of high-performance water
229
reducing agent.
(7) Necessity
There are many uses for coal ash and it is also used outside the construction industry,
but it is still used in only small quantities for purposes other than in concrete. It is
therefore desirable for coal ash to be used in the construction industry.
The use of coal ash as an admixture for concrete does not emit especially large volumes
of carbon dioxide.
[Examples of Usage]
1) Retaining walls for a recycled material’s storehouse in a cement factory.
2) Various foundation construction work in a power plant.
3) Paving inside an ash center estate.
4) L-shaped retaining walls (a factory-produced product.)
[References]
1) Katsutoshi Ichikawa, et al.: Effects of Difference of Curing Environment to the
Strength Characteristics of Concrete that Uses Large Quantities of Coal Ash, Cement &
Concrete Thesis Collection, No.51, 1997.
2) Masahiro Kato, et al.: On-Site Test Construction of Concrete Blended with Large
Quantities of Coal Ash, Japan Society of Civil Engineers 55th Annual Academic Seminar
Thesis Collection, 2000.
3) Yoshimasa Suzuki, et al.: Examples of Actual Constructions of CA Concrete Blended
with Large Quantities of Coal Ash, 3rd Tokyo Kanto Regional Taiheiyo Cement
ready-Mixed Concrete Technology Conference, 2002.
4) Masafumi Fujiwara, et al.: Use of CA Concrete in Actual Structures, Concrete Techno,
Vol.21, No.5. 2002.
5) Hiroshi Iwaki, et al.: Use of CA Concrete that Uses Large Quantities of Coal Ash in
Foundation Construction, CEM’S, 2002.
6) Akihiko Karazawa, et al.: Investigation into the Use of Fly Ash Original Powder for
Instantaneous Demolding Concrete Products, Japan Society of Civil Engineers 57th
Annual Academic Seminar Thesis Collection, V.378, 2002.
6) Hiroaki Mori, et al.: Hardening Characteristics of Steam-Cured Concrete that Uses
Fly Ash original Powder, Japan Society of Civil Engineers 57th Annual Academic
Seminar Thesis Collection, V.379, 2002.
230
This section applies to the use of original powder which has not been subjected to
classification, or other processing, as subgrade material.
The quality standards for road-bed material that uses coal ash must conform to the
Pavement Construction Guidelines. The test methods for each of the quality items
stipulated in the quality standards must conform to the stipulations laid down in the
Guidelines for Pavement Test Methods.
Quality tests are to be carried out on each type of material classified on the basis of
particle size and investigations must be implemented to ascertain whether or not the
material is suitable for use in the specific type of subgrade (depending on the traffic
volume).
The coal ash is to be blended with recycled asphalt concrete aggregate and then
adjusted so that the recycled subgrade material satisfies the required quality levels and
the quality standards must conform to the stipulations laid down in the Technical
Guidelines for Plant Recycled Paving. A summary of these quality standards are provided
in Tables 3.3.2-1 and 3.3.2-2.
Construction
Method,
Material
Granular
Revised
Unconfined
strength MPa (kgf/cm２)
CBR %
Subgrade 20 or more１)
−
Material, Crusher-run, etc.
Cement
Stabilization
6 or less
２)
−
Material Age 7 days,1.0
−
(10)
Process３)
Lime Stabilization Process３)
PI
compression
−
Material Age 10 day, 0.7
−
(7)４)
1) 10 or more with simple paving
3) None with simple paving
2) 9 or less with simple paving
4) 0.5 (5) with cement concrete paving
The prescribed particle size is required with the crusher-run. It is also desirable to
attain a revised CBR of 10% or more and a PI (plasticity index) of 9 or less for cement
231
and between 6 and 18 for coal ash.
Construction
Method, Material
Revised
CBR %
Unconfined
Marshall
compression
Stability
Other
Quality
Level Standards
MPa kN (kgf)
strength
(kgf/cm２)
Size
Controlled 80
Crushed Stone
Hot
Asphalt
or
−
more１)
―
―
3.43
Stabilization
(350)
more
or Flow value 10 to
40
Process
Cement
PI4 or less
−
Air void 3 to 12%
−
Material
Age
7
−
−
Material Age 10
−
−
days２) 2.9 (30)
Stabilization
Process
Lime Stabilization
−
Process
days3) 1.0 (10)
1) 60 or more with simple paving.
2) 2.5 (25) or more with simple paving, 2.0 (20) with cement concrete paving.
3) 0.7 (7) with simple paving.
It is necessary for the aggregate used as subbase course material to have an abrasion
loss of 50% or less and the size-controlled crushed stone must have the predetermined
particle size. It is also desirable for the aggregate used in the stabilization process to
have a revised CBR value of 20% or more (excluding asphalt,) a PI of 9 or less (6 to 18
for lime) and a maximum particle diameter of 40mm or less.
To conform to the description already provided in Section Three, 3.1.1 (2) (2).
1) The composition of coal ash differs depending on the region in which it is produced
and the properties and content also differ: particularly, the toxic substances, including
heavy metals when the coal ash is used for subgrade material. It is therefore necessary
to make sure that the substances in coal ash are thoroughly verified prior to use.
232
2) The regions in which coal ash is produced are limited, so it is necessary to investigate
and ascertain if sufficient amounts of coal ash for the scale of the construction can be
obtained and that coal ash can be stored in an environment that maintains its quality.
(4) Technology Used
1) Design
The methods and procedures for the design of subgrades using coal ash must conform to
the stipulations laid down in the Guidelines for Pavement Design and Construction.
2) Construction
The methods and procedures for construction must conform to the stipulations laid
down in the Pavement Construction Guidelines, etc.
There are many examples of clinker ash being used in subbase courses, with
consideration to the particle diameter and physical characteristics. It is also possible to
use a fine aggregate admixture for asphalt stabilization processing and fine granules of
size-controlled crushed stone as supplementary material. However, it is necessary to
confirm that the predetermined quality standards and environmental safety standards
required for the purpose of use are satisfied.
3) Maintaining Records and Repeated Usage
The purchaser must save the construction diagrams, quantity charts and all other
design documentation together with the results of tests implemented on the coal ash so
that they can be used if the material is to be recycled or disposed of.
The purchaser must confirm that the material satisfies all environmental standards for
soil when the material is to be repeatedly used or disposed of and this must be carried
out in an appropriate manner in accordance with the details listed in the design
documentation created for the original construction.
[References]
1) Japan Society of Civil Engineers: The Current Situation and Perspectives on the
technology for Using Coal Ash as Material in Public Works Projects—Backfill,
Embankment Fill, Soil Improvement Material, March 1990.
2) Ash Information and Survey Center: Guide to the Effective Use of Coal Ash,
General Industry Volume, March 1989.
233
3.3.3. Road Bed Materials
classification or other processing as road bed material.
The quality standards for subgrade material that uses coal ash must conform to the
Pavement Construction Guidelines. The tests for the various quality items listed in the
quality standards must be implemented in accordance with the methods laid down in
the Guidelines for Pavement Test Methods.
Coal ash is used as a frost blanket material and as a filter layer material. As a material
for the frost blanket, pit-run gravel, crusher-run, or the like have good drainage levels
and are effective in preventing freezing. A yardstick for materials that help prevent
freezing is shown in Table 3.3.3-1.
In addition to referring to the conditions listed in Table 3.3.3-1, it is also necessary to
confirm with freeze tests that freezing does not occur easily when coal ash is used in the
frost blanket.
Table 3.3.3-1. Yardstick for Material that Helps Prevent Freezing
Material
Sand
Summary
The percentage that passes through a sieve with a mesh size of
75µm must be 6% or less in all test materials.
Unscreened
Gravel
Of all test materials, 9% or less of the gravel that passes
through a sieve with nominal size of 4.75mm, passes through a
sieve with nominal size of 75µm.
Crusher-Run Of all test materials, 15% or less of the gravel that passes
through a sieve with nominal size of 4.75mm, passes through a
sieve with nominal size of 75µm.
(Source: Japan Road Association, Pavement Construction Guidelines)
234
River sand, unscreened gravel or good-quality mountain sand (10% or less passes
through a sieve with a nominal size of 75µm) are used as filter layer material. Clinker
ash and cinder ash are suitable materials for this purpose, though it is necessary to
investigate and confirm the particle size of these materials, to determine whether they
can be used or not.
The environmental safety standards for coal ash used as subgrade material must
conform to the stipulations laid down in 3.1.1 (2) (2), Chapter 2.
(3) Technology Used
1) Design
The design must conform to the stipulations laid down in the Guidelines for Pavement
Design and Construction.
2) Construction
The methods and procedures for construction must conform to the stipulations laid
down in the Pavement Construction Guidelines, etc., depending on the usage of coal
ash.
[References]
1) Japan Society of Civil Engineers: The Current Situation and Perspectives on the
technology for Using Coal Ash as Material in Public Works Projects—Backfill,
Embankment Fill, Soil Improvement Material, March 1990.
3.3.4. Embankment Fill Materials
This section applies to the use of non-graded base granules in embankment fill.
Embankment structures have various functions, depending on their purpose.
Unprocessed coal ash that is used in embankment fill must have the same performance
levels required of other embankment material according to the policy and standards of
each embankment structure.
The types of embankment fill and their functions are shown in Table 3.3.4-1.
Table 3.3.4-1. Types of Embankment Fill and their Functions
Type
Main Role
Required Conditions
235
General Slope Grade
Road
(1)
Embankments Supporting
resistance
traffic loads
Railway
Sufficient
(2)
Low
bearing
levels
of
1:1.5 to 1:2.0
subsidence and unequal
Embankments
and settling
Reclaimed
Building
Land
facility loads
1:1.8 to 1:2.0
(3) Slope stability
Embankments
Refer to the following specifications, guidelines and standards for details on the
quality standards required of embankment fill.
-
Land, Infrastructure and Transportation Ministry: Common Specifications on
Public Engineering Works Construction.
-
Ministry of Agriculture, Forestry and Fisheries: Planning and Design
Standards for Soil Improvement Projects.
-
Japan Highway Public Corp.: Design Guidelines Edition Two, Common
Specifications on Public Engineering Works Construction.
-
Urban Development Corp.: Common Specifications on Construction Works.
-
Japan Road Association: Earthmoving—Soil Quality Survey Guidelines.
-
Japan Road Association: Earthmoving—Slope and Incline Stabilization
Guidelines.
Required quality levels for each usage application are to conform to the descriptions
already provided in 3.1.1 (2) (2), Chapter 2.
The factor over which the most care must be taken when using recycled materials for
embankment fill is the environmental safety of the soil. It is therefore necessary to
implement environmental safety tests on the coal ash that makes up this material to
confirm that it satisfies all necessary standards. If it does not satisfy the environmental
safety standards, then it cannot be used as embankment fill in an unprocessed condition.
The environmental safety evaluations conform to the stipulations already laid down in
3.1.1 (2) (2), Chapter 2.
(3) Technology Used
There are no specific stipulations with regard to the design standards of embankment
fill that contains unprocessed coal ash, but it must conform to the guidelines and
standards, or the like, issued by the purchaser. Also, requirements such as the quality
control of rolling, construction management and the selection of construction machinery
must conform to the specifications stipulated by the purchaser, and it must be verified
beforehand that construction is actually possible by implementing test constructions.
236
The requirements for embankment fill material differ depending on its usage (roads,
railways, residential areas, etc.) and the location of usage (upper part of road, lower
part of road, etc.,) but the basic requirements are providing stability against landslides,
sufficient compaction strength and having enough bearing resistance to withstand
traffic and other heavy loads. All of these factors depend on the strength of the
embankment fill. Rolling at the time of construction is an extremely important point in
guaranteeing the strength of embankment fill. When coal ash is added with appropriate
amount of water and rolled, it shows sufficient strength as embankment fill. The
strength of coal ash used for embankment fill differs greatly depending on its
compaction density. Coal ash embankment fill that is not rolled and has a low density,
will not provide much strength and there is a possibility that its use will lead to
landslides and other accidents. When sufficiently rolled, an N value between 10 and 50
is obtained.
[References]
1)
The
Japanese
Geotechnical
Society:
Embankment
Surveys,
Design,
and
Construction.
2) Public Works Research Center: Technical Manual for Using the Soil Generated
through Construction (2nd Edition).
3) The Japanese Geotechnical Society: The Effective Use of Waste and Soil Generated
through Construction in Embankment Engineering.
3.3.5. Filler Materials
classification, or other processing, as a filler.
Filler is contained within a space surrounded by steel or concrete members and
constitutes part of a structure serving as a weight supplement or filler. It is used to fill
these enclosures.
However, in special cases where it is installed in such a way that it does not come into
direct contact with the ground (when it is completely sealed off on all sides and the
base,) it is regarded as “sealed filler” according to the Standards for Implementing
Surveys
and
Countermeasures
into
Soil
237
and
Underground
Water
Pollution
(Environment Agency Water Quality Board, January 29th 1999,) and the amounts of
elution shown in Table 3.3.5-1 may be used.
238
Table 3.3.5-1. Effluent Standards for Sealed Filler
Item
Elution Values II
Cadmium
0.3mg/L
All cyanide
１mg/L
Organic
１mg/L
phosphorous
Lead
0.3mg/L
Hexavalent
1.5mg/L
chromium
Arsenic
0.3mg/L
Total mercury
0.005mg/L
Alkyl mercury
PCB
0.003mg/L
Thiraum
0.06mg/L
Simazine
0.03mg/L
Thiobencarb
0.2mg/L
Selenium
0.3mg/L
(3) Technology Used
The required quality levels of filler differ depending on whether it is to be used as filler
or a weight supplement. It requires fluidity, strength and incompressibility when used
as filler and weight when it is used as a weight supplement. No quality standards exist
for this and in most cases the design will reflect the requirements, depending on its
purpose.
It is necessary to investigate whether usage as powder or usage as slurry is required,
depending on the possibility of pouring it from above, conveying it to the required
location and the local terrain on the construction site. When usage as powder is selected,
it is necessary to add moisture and ensure that rolling is carried out thoroughly.
Because air pressure pipes are used with usage as slurry, it is necessary to investigate
the quality levels required for construction (fluidity, slaking, etc.)
3.3.6. Backing Materials
classification or other processing as backing material.
239
Backing material is used at the rear of retaining walls and underground structures, etc.
and between excavation surfaces and structures. As backing material becomes part of
the surrounding soil, it must conform to the environmental safety standards and test
methods stipulated in 3.1.1 (2) (2), Chapter 2.
(3) Technology Used
The quality levels required of structural backing materials are the same as the quality
levels stipulated in Table 3.1.1-1, Chapter 2 that shows the required quality levels of
embankments and levees. When applicability is an important factor, the coal ash should
be turned into slurry.
3.3.7. Soil Quality Improvement Materials
classification or other processing as soil improvement material. Soil improvement
material is coal ash, in powder or slurry form, blended with soft soil in order to harden it
with the self-hardening nature of coal ash. There are also cases where it is mixed with
cement in order to improve long-term strength through pozzolanic reactivity.
Blend selection tests must be carried out on the cement and coal ash. However, the
standard age of the material is the same as coal ash improvement material. It is also
necessary to confirm the self-hardening nature that affects the soil hardening
performance when it is used as a soil improvement material. The chemical properties of
coal ash differ depending on where the coal was mined, the method in which it was
incinerated and the amount of SiO2, Al2O3 and CaO contained within the coal, which are
all related to self-hardening strength. The following three reactions are the major
factors in determining the strength of the self-hardening nature of coal ash.
(1) Water hydration reaction of coal ash.
(2) Pozzolanic reactivity between the coal ash and silica or alumina.
(3) Ettringite formation reaction.
It is also necessary to confirm the strength levels attained with the use of laboratory
tests beforehand, in consideration of compatibility between the soil and the coal ash.
The environmental safety standards and test methods must conform to the descriptions
provided in 3.1.1 (2) (2), Chapter 2. There are cases where heavy metals and other toxic
240
matters contained in coal ash exceed the standards depending on where it was mined,
so it is advisable to establish a system of shipment administration similar to the one
shown in Fig. 3.3.7-1.
Fig. 3.3.7-1. Example of a System of Shipping Coal Ash Soil Improvement Material
(3) Technology Used
It is necessary to implement blending tests on the coal ash used as soil improvement
material and confirm the results before it is used. The test methods are to conform to
the stipulations laid down in JGS T 821-1990, Creating Non-Compacted Stabilized Soil
Samples, (The Japanese Geotechnical Society).
[Examples of Usage]
1) 641 tons used on land that had been pre-processed with soil dredged from the bay.
(Okayama Prefecture)
[References]
1) Choku Saito: Coal Ash Utilization Technology by Chugoku Electric Power Co. Inc.,
CCT Journal, Vol.4, November 2002.
2) Chugoku Regional Development Bureau, Ministry of Land, Infrastructure and
Transport: Manual for Designing Stabilizer that Uses Coal Ash, November 2001.
3) Chugoku Electric Power Co. Inc.: “Geo Seed” (soil improvement material,) Chugoku
Electric
Power
Company
http://www.energia.co.jp/energy/general/eco/eco7-5.html
241
Ltd.
Homepage:
4. Waste Glass
Overview of Waste
To conform to the stipulations laid down in 5, Chapter 2.
4.1 Crushing Processing
Refer to the descriptions in 5.1, Chapter 2, for details on the crushing process for waste
glass.
4.1.1 Aggregate for Asphalt Pavement Surface Course
Asphalt admixture containing glass cullet makes the best use of the reflective
characteristics of glass cullet (reflects light) and is used in road surface course. Road
surfaces that reflect light improve visibility for drivers and pedestrians. They also have
the ability to make drivers and pedestrians more aware of safety at night, on badly-lit
mountain roads and at junctions with bad views. There are consequently many cases in
which paving blended with cullet is used on roads. The majority of these roads have a
paving design traffic volume category of between 250 and 999 vehicles/day/direction
(equivalent to the B traffic volume category in the former guidelines). Although still
limited to test construction, it can also be used on roads with heavy traffic (roads with
an
actual
paving
design
traffic
volume
of
between
1,000
and
2,999
vehicles/day/direction) as long as flow-resistance measures are implemented.
(2) Test Methods
The quality standards must conform to the stipulations laid down in the Guidelines for
Pavement Design and Construction and the Guidelines for Pavement Construction, etc.,
depending on the type of road paving for which it is to be used.
The environmental safety standards and test methods must conform to the stipulations
laid down in 1.1.1 (2) (2), Chapter 2. Glass has very little toxic content from the
viewpoint of environmental safety, but there is cause for anxiety about toxic effluents if
impurities are mixed in with it. It is therefore necessary to use glass cullet that has
been thoroughly cleansed. Also, glass cullet contains sharp edges, so it is advisable to
use material that has been subjected to rounding in order to guarantee safety in the
handling process or in actual usage as a pavement.
(3) Technology Used
An example of the composition of asphalt admixture that contains glass cullet is shown
242
in Table 4.1.1-1. Peeling resistance (residual stability) is lowered when the percentage
of glass cullet that is used in the blend becomes higher. The limit for the amount of
cullet that can be used is therefore approximately 10%. If more is used, there are cases
where the asphalt admixture will not satisfy the required standards.
243
Table 4.1.1-1. Blend and Composition of Admixture that Uses Cullet
By Blend
Aggregate
Blend Ratio
Standard
A-1
A-2
B-1
B-2
Crushed Stone #6
37.5
32.5
27.5
37.5
37.5
Crushed Stone #7
20.0
15.0
10.0
20.0
20.0
(%)
Coarse Sand
32.0
32.0
32.0
20.0
10.0
Fine Sand
5.0
5.0
5.0
6.5
6.5
Stone Powder
5.5
5.5
5.5
6.0
6.0
Cullet
13.2
to
-
5.0
10.0
-
-
4.75
to
-
5.0
10.0
-
-
2.36mm
or
-
-
-
10.0
20.0
6.4
6.4
6.3
6.1
5.9
2.338
2.342
2.322
2.344
2.341
4.5
3.7
4.1
4.1
3.9
Saturation Level (%)
76.2
79.6
77.5
77.0
77.3
Stability (kN)
11.5
12.1
10.3
10.9
9.4
30
30
4.75mm
Cullet
2.36mm
Cullet
less
Optimal As Volume (%)
Marshall Stability Level (g/cm
３
)
Air Void (%)
Flow Value (1/100 ㎝)
27
Residual Stability (%)
Dynamic Stability (times/㎜)
Skid Resistance
Coefficient (BPN)
95.8
94.4
490
320
Before
63
57
Before
-
94.2
89.5
320
-
57
58
60
53
51
51
53
Polishing
Reflectivity (%)
86.0
26
70
Polishing
After
29
5.19
4.83
5.11
5.33
4.99
4.98
4.89
5.12
4.92
4.67
Polishing
After
Polishing
The results of a survey into a follow-up of post-usage paving containing glass cullet
are shown in Table 4.1.1.4-2 (used on a road with a paving design traffic volume of
244
between 1,000≦T<3,000 vehicles/day/direction.)
Table 4.1.1-2. Results of a Survey into Post-Usage Road Surface Conditions
Paving
Item
Containing
Dense-Particle Asphalt
Glass Cullet
At
Transverse
Shape
σ
Admixture (13)
4
years At
4 years later
Constructi later
Constructi
on
on
1.8
1.97
−
−
1 to 2
2 to 4
−
−
58.4
60.7
62.0
64.0
of 20 ㎞
/h
0.56
0.67
0.60
0.68
40 ㎞
0.51
0.62
0.54
0.64
0.47
0.60
0.50
0.62
(mm)
Horizontal Shape (mm)
Skid Resistance
Coefficient (BPN)
Coefficient
Dynamic
Friction(µ)
/h
60 ㎞
/h
Surveillance of the road surface indicated that a certain amount of dispersion of glass
aggregate was recorded after two years of use, but there was no difference in the
condition of the road surface compared to an ordinary pavement (dense-particle). The
reflective effect and visibility of the road surface remained good, four year after
construction.
There are two methods of mixing glass cullet in asphalt plants—the indirect heating
method and the direct heating method—and outlines of these methods are shown in
Table 4.1.1-3.
Table 4.1.1-3. Cullet Mixing Methods
Type
Indirect Heating Method
Direct Heating Method
Mixi A measured amount of cullet is placed The cullet is passed through a dryer in the
ng
in a mixer at room temperature and this same way as ordinary aggregate where it is
Met is then heated and dried with the heat heated and dried and it is then passed
hod exchange
from
a
high-temperature through a vibration sieve to be classified,
substance until it turns into admixture. measured and mixed.
245
Adva 1)
ntag
Switching
between
es
the
production
line 1) As heating and drying are carried out by
admixture
and
ordinary
admixture using cullet is a simple
2) The amount of cullet mixed is
3) Production equipment for recycled
aggregate can be used.
recycled
aggregate
vibration
shards
managed without failure.
As
moisture content is relatively high.
2) As the admixture is graded with a
task.
4)
a dryer, there is no problem even if the
sieve,
with
all
large
oversized
diameters
glass
are
removed.
3) Cold hopper aggregate supply facilities
mixing
can be used if available.
machinery can be used, it can be
stored at plants that have the type of
aggregate storage silos that are most
common in cities.
Disa 1) Cullet with high water content levels 1) All heated aggregate that is stocked
dvan
cannot be mixed and large quantities
must be removed before the production
tage
of cullet cannot be mixed in.
line can be switched between ordinary
s
2) As the cullet is placed directly into
the mixer, glass shards with large
diameters
are
included
in
admixture and admixture using cullet,
which lowers efficiency.
the 2) There is a possibility that discrepancies
may appear in the amount of cullet
admixture.
mixed in admixture at the beginning of
manufacture and in order to prevent
this, it is necessary to remove the heated
aggregate until it becomes stable, but the
removed aggregate cannot be used for
general purposes.
One anxiety with admixture that uses glass cullet is the fact that the cullet contained
within it is crushed into fine powder when rolling is carried out with a road roller.
However, this problem has hardly been recognized in the past construction examples up
until now. It is also necessary to beware of the glass cullet used in road surfaces being
dispersed by moving vehicles.
It has been verified that recycled aggregate that contains crushed and classified glass
can be used in the same way as recycled aggregate in asphalt concrete. However, it is
246
advisable to keep the amount of glass mixed in the admixture to 10% or less in
consideration of the lowered performance of asphalt admixture that contains large
volumes of glass cullet and the amount of cullet in the recycled admixture that could be
accumulated due to repeated recycling of the pavement.
(1) Usage Results
There are many examples of asphalt admixture containing glass cullet being used. The
points for consideration that have arisen from these examples include the need to
suppress the amount of glass cullet that peels off and the need to prevent the dispersion
of glass cullet by moving vehicles.
(2) Supply
Glass cullet is mostly produced by glass bottle production facilities located in large cities,
so it is necessary to implement surveys into whether or not the required amount can be
obtained in an efficient manner.
(3) Repeated Use
The following facts were obtained from the results of an investigation at the time of
constructing a general public roadway with the use of material recycled from an
eight-year-old pavement that contained glass (the pavement containing glass was torn
up, crushed, classified and then recycled as glass aggregate).
1) Results indicate that the condition (density, particle size, asphalt volume, acicular
level of collected asphalt, etc.) of recycled aggregate that contains glass is almost the
same as ordinary recycled aggregate.
2) Tests on the condition of the aggregate (the immersion Marshall test and wheel
tracking test) satisfied the standards, but because dynamic stability deteriorates when
the percentage of glass in the mixture is increased, a maximum of 10% of glass should
be used.
3) The brightness levels, which is the reflection characteristic of road surface, achieved
higher values than that of ordinary asphalt pavement.
4) The workability, behavior during rolling, quality of the finished condition and other
construction performance levels were almost the same as ordinary asphalt admixture.
These results therefore indicate that this material can be used repeatedly as long as no
more than 10% of glass is mixed in.
247
There are cases where admixture using glass cullet is more expensive than that using
natural aggregate.
(5) Necessity
The use of cullet as a construction material will lead to consumption in vast amounts, so
there are high expectations for its general use in the future.
Glass is inorganic and its composition is similar to that of stone. Also, glass cullet is
manufactured by finely crushing waste glass bottles and separating the resultant
product by the size of the particles, so electricity is consumed during the crushing
process. Carbon dioxide is therefore emitted through this use of electrical power.
[Examples of Usage]
1) Uchiyama, Ikesaki and Iida: Characteristic of Admixture Containing Glass and Test
Paving, 20th Japan Road Association Seminar Thesis Collection, 1993.
2) Yukawa, Iyama and Shimoda: Reusing Glass Bottle Cullet for Asphalt Pavement,
Pavement, April 1997
3) Uchiyama, Ikesaki and Nagashima: Long-Term Usability of Asphalt Pavement
Containing Class, Pavement, October 1998.
4) Okamoto, Haritani and Kumode: Reflective Characteristics of Asphalt Admixture
Containing Glass Cullet, Pavement, March 1999.
5) Uchiyama, Yamato and Suzuki: Recycling Paving Containing Glass Eight Years after
Construction, 24th Japan Road Association Seminar Thesis Collection, 2001.
[References]
1) Takeshita, Nose, Seki and Sano: Examples of Installing Reflective Paving, Public
Works Research Institute 49th Annual Academic Seminar, 1994.
2) Furukawa and Fujibayashi: Characteristic of Asphalt Admixture Containing Waste
Glass Aggregate, 21st Japan Road Association Seminar Thesis Collection, 1995.
3) Abe and Yoshida: Examples of Asphalt Paving Construction Using Crushed Glass,
21st Japan Road Association Seminar Thesis Collection, 1995.
4) Shimamura, Nakada and Morita: Examples of the Use of Glass Waste in Final
248
Processing Sites for Asphalt Pavement, 21st Japan Road Association Seminar Thesis
Collection, 1995.
5) Omichi, Fujii and Uchida: Observations Related to hot Admixture that Uses Recycled
Glass Aggregate, 22nd Japan Road Association Seminar Thesis Collection, 1997.
6) Ichikawa, Kaneshiro and Sasaki: Characteristic of Asphalt Concrete Mixed with
Waste Glass, 22nd Japan Road Association Seminar Thesis Collection, 1997.
7) Imai, Masui and Hiyama: Some Observations Regarding Asphalt Admixture
Containing Glass Particles, 22nd Japan Road Association Seminar Thesis Collection,
1997.
8) Nikumaru, Handa and Tanaka: Use of Non-Combustible Glass for Asphalt Pavement,
22nd Japan Road Association Seminar Thesis Collection, 1997.
9) Iyama and Shimoda: Reusing Glass Bottles for Asphalt Pavement, 22nd Japan Road
Association Seminar Thesis Collection, 1997.
10) Okamoto, Haritani and Kumode: Examples of the Construction of Asphalt
Admixture Containing Waste Glass, 22nd Japan Road Association Seminar Thesis
Collection, 1997.
11) Uchiyama, Ikesaki and Nagashima: Long-Term Usability of Pavement Containing
Glass and the Potential for Reuse, 22nd Japan Road Association Seminar Thesis
Collection, 1997.
12) Tanigoe, Sugimoto and Okumura: Asphalt Pavement that Uses Glass Scrap, 22nd
Japan Road Association Seminar Thesis Collection, 1997.
4.1.2 Base Course Aggregate for Resin Pavements
This section applies to the use of resin admixture containing glass cullet (polymer
paving material that uses cullet partially or totally in the aggregate) in pedestrian
pavements.
The quality standards for polymer resin pavement (Polymer Material for Pedestrian
Paths: Recommended Standards and Construction Guidelines, 1993, Polymer Paving
Association) are shown in Table 4.1.2-1.
249
Table 4.1.2-1. Quality Standards for Polymer Paving Materials
Item
Skid
Resistance
Adhesion
Abrasion
Permeabilit
y
Paving Type Accelerate Coefficient (BPN Value) (Strength of Loss
adhesion)
(Amount of (Permeabili
d
Weatherin
Damp
Dry
Wear)
(N/cm2)
g
(㎎)
ty
Coefficient)
(㎝/sec)
Resin Mortar
Paving
100<
Good
(65<)2)
45<
or
undergroun
1,000>
−1)
1,000>
1 x 10−２<
d crushing
100<
Natural
Gravel
Good
(65>)2)
45<
Paving
or
undergroun
d crushing
Notes: 1) Not specified, as the paving material itself does not have this function, or
because it is too difficult to measure.
2) Skid resistance coefficients for dry surfaces are provided in parenthesis for
reference purposes.
The properties of polymer paving material that contains glass cullet are shown in
Table 4.1.2-2.
Table 4.1.2-2. Properties of Polymer Paving Material
Item
Characteristic
Remarks
Values
Bending
8.6 (MPa)
JIS A 5209-1994
Strength
Compaction
29.2 (MPa)
Strength
Skid Resistance
Coefficient
Permeability
95–98 (dry)
ASTM E-303
49–54 (wet)
ASTM E-303
2.0 x 10−２㎝/sec
Conforms to JIS A
Coefficient
Abrasion Loss
1218
0.011g
JIS A5209-1994
250
It is possible to install polymer paving while making the best use of its color, in
consideration of the surrounding scenery. It is also used as drainage pavements and
other types of functional pavements.
It is necessary to select polymer which is most suitable for pavements having excellent
durability and weather-resistance qualities. Also, glass cullet has low water absorption
rates and does match well with polymer, so it is necessary to consider levels of adhesion
with glass cullet in the polymer selection process.
1) This is mostly used for paths in parks and pedestrian paths, etc. It is necessary to
guarantee safety, particularly for pedestrian paths, in order to be prepared for cases of
infants and/or senior citizens falling. This will include rounding off the crushed surfaces
of the glass aggregate and using a top coat on the surface of the path.
2) It is necessary to conduct investigations into the possibility of repeated use.
[References]
1) Hyodo and Ito: Paving that Uses Waste Glass, 21st Japan Road Association Seminar
Thesis Collection, 1995.
2)
Nagabuchi,
Fujimura
and
Yoshimura:
Investigations
into
Reflective
Scenery-Friendly Permeable Pavement that Uses Waste Glass Bottles, etc., 22nd Japan
Road Association Seminar Thesis Collection, 1997.
3) Hirota, Onoda and Nagase: Examples of the On-Site Use of High-Brilliance Reflective
Pavement—Improved Visibility, 22nd Japan Road Association Seminar Thesis
Collection, 1997.
4) Omichi, Uto and Kosaza: Resin Paving that Uses Recycled Glass Material, 22nd
Japan Road Association Seminar Thesis Collection, 1997.
5) Yoshimura; Examples of the Use of Waste Glass Bottle for Pavement, 22nd Japan
Road Association Seminar Thesis Collection, 1997.
6) Namba and Yoshimura: Laminated Color Resin Mortar Pavement that Uses Waste
Glass Bottle Cullet, Paving, May 1998.
7) Uto, Fukada and Nomoto: Use of Recycled Glass in Pavement, 24th Japan Road
Association Seminar Thesis Collection, 2001.
251
4.1.3 Aggregate for Interlocking Blocks
This section applies to the use of glass cullet as interlocking block aggregate.
The Interlocking Block Pavement engineering Association quality standards and
dimension standards are shown in Tables 4.1.3-1 and 4.1.3-2.
Glass cullet is used as a part of concrete aggregate.
Table 4.1.3-1. Strength and Permeability Coefficients for Interlocking Blocks
Type
Bending
Permeability
Strength
Coefficient
Ordinary Interlocking Blocks
4.9N/mm２
――
Permeable Interlocking Blocks
2.9N/mm２
1 x 10−２cm/sec or
more
Table 4.1.3-2. Dimensional Deviation for Interlocking Blocks
Type
Length
Width
Thickness
Ordinary Interlocking Blocks
±3mm
±3mm
±3mm
Permeable Interlocking Blocks
+5mm,
-1mm
As alkali aggregate reactions may occur in glass cullet, it is necessary to make sure
that the amount of alkali in the concrete is limited to 3kg/m3 or less prior to usage.
(3) Technology Used
1) Design Methods
The procedures for designing interlocking block pavements using glass cullet are the
same as those for ordinary interlocking block paving.
Construction methods are the same as those for ordinary interlocking block paving.
3) Maintaining Records and Repeated Use
When glass cullet is used for interlocking block pavements, the purchaser must store
the used material charts (including the results of tests on the glass cullet,) the
construction diagrams, the design mix formula and all other records relating to
252
construction so that they can be used when the pavement is recycled for repeated use, or
disposed of.
There is very little fluctuation in the quality of glass cullet, so recycling it should not
pose any problems.
1) Glass cullet does not adhere well to cement mortar, so it is necessary to either limit
the amount of glass cullet that is blended in or use polymer concrete in order to
manufacture blocks that satisfy the required standards. The cost of manufacturing
blocks with the use of polymer concrete is higher than the cost of manufacturing
ordinary interlocking blocks.
2) It is possible to create interesting designs by using the glass on the surface to reflect
light. If, on the other hand, glass is not required on the surface layer, then it is
advisable to use ordinary mortar instead of finishing the surface with glass cullet. It is
necessary to round off the crushed surfaces of glass cullet when it is to be used on the
surface of the pavement to guarantee safety in the event of pedestrians falling.
3) It is possible to reuse blocks as they are, if there is no damage. Also, if the
permeability capabilities of permeable blocks deteriorate, it must be washed with
high-pressure water. Damaged blocks can be crushed and used again as block material
or blended with subgrade material.
4.2.1 Tree-Planting Water Retention Materials
Foam waste glass is both light and strong owing to its porous, continual-gap structure
and it is possible to control its density, water absorption and drainage qualities,
depending on the conditions of manufacture. Of the different types of foam glass
available, glass with high levels of water absorption, in particular, is used as a
water-retaining material for planting trees on rooftops and on slopes, etc. Foam glass
comes in various forms, including blocks, coarse particles and flat boards.
It is effective as a countermeasure against the heat island effect and as a material to
encourage the restoration of ecosystems when it is used for planting trees on the
rooftops of high-rise buildings, many of which can be found in metropolitan areas. The
compulsory planting of vegetation on rooftops has become a municipal bylaw in Tokyo
and some other cities, and vegetation is now in progress.
253
(A) Improving the Quality of Glass Cullet
When glass cullet is used as a raw material, it is important to improve the quality of the
glass cullet that is collected through sorted refuse collection activities in municipal
areas. Some of the foreign objects that get included in it and cause problems are
non-ferrous metal, ceramics, stone and impure glass (crystallized glass, such as
fire-resistant crockery and cooking utensils, electric bulbs, fluorescent lighting, etc.) It
is very difficult to remove all of the foreign objects that are mixed in with empty bottles
during the collection process and this leads to the problems of affecting production
facilities and yield ratios. In order to increase the usage of glass cullet, it is necessary to
establish a complete prevention of foreign objects being mixed in it at the early stages of
production and to improve quality during the cullet processing stage.
Two points for future consideration are to establish a system that completely eradicates
the problem of foreign objects getting mixed in with cullet at the stage where consumers
and local authorities sort and collect refuse and to increase awareness and
enlightenment activities.
(2) Cost of Transportation
The fact that production costs are increased due to the cost for transporting raw
material (glass cullet and glass bottles,) the cost of transporting foam glass is a big
problem. In order to prevent increased product costs, we must consider the necessity of
establishing a stable system of supply and demand.
(2) Examples of Usage
(3) Rooftop Vegetation
When foam glass in its block form or coarse particle form is used, it must be placed on a
sealing sheet or waterproof sheet and this is then covered with a mat to prevent soil
draw-out in order to create a double layer that provides both drainage and moisture
retention abilities. A layer of soil is then laid on top of this drainage/water-retention
mat into which trees and other vegetation are planted to achieve rooftop gardens. When
foam glass in its flat board form is used, a drainage mat made of polyester, which is laid
on the sealing sheet or waterproof sheet, serves as the water-retention layer while flat
board foam glass is set thereon as a moisture retention layer.
Although there are limits to the amount of load that can be supported by the floor when
tree-planting is carried out on rooftops, (the standard load limit is 80kg per square
meter) there are examples in which the use of foam glass reduces this load by up to
30kg.
When vegetation is used together with rooftop gardens, a soil layer of approximately
one meter in depth is generally provided for water-retention capabilities in order to
254
cultivate both small and large trees. However, as foam glass has excellent
water-retention capabilities, there are examples where the soil layer has been reduced
by more than half, to between 30cm and 50cm and this enables huge reductions in the
load being placed on the building.
Foam Glass Board
Block and Coarse Particle Foam Glass
Fig.4.2.1-1. Rooftop Vegetation Using Foam Waste Glass1)
(4) Usage for Vegetation on Slopes
Two different methods of vegetation on bedrock slopes have been implemented using
foam waste glass: one in which coarse-particle foam glass is mixed in with vegetation
base material, and: another in which foam glass is embedded into cement boards to
make glass boards. Glass boards are effective in preventing the slippage of thick soil
layers and have better water-retention capabilities.
The water absorption levels of foam glass having porous, continuous-gap characteristics
is excellent, and this provides the soil that is needed for cultivating vegetation to
maintain high levels of ventilation, providing a favorable environment for the growth of
roots.
Foam glass is chemically stable and does not elute toxic substances. Moreover, it is
light-weight and has excellent durability and usability. The use of foam glass in the
vegetation base material laid on slopes consequently improves water-retention
capabilities in the long term, which facilitates the growth of vegetation.
[Examples of Usage]
1) The village of North Hata, Matsuura-gun, Saga Prefecture: Vegetation planting on a
slope as part of a construction product to improve the village road between Tokusue and
Osugi.
2) The village of North Hata, Matsuura-gun, Saga Prefecture: Slope construction
alongside the Hobashira Agricultural Road (test construction).
255
3) City of Imari, Saga Prefecture: Slope construction on a slagheap in flat area in
Kunimi (test construction)
4) Across Fukuoka, Fukuoka Prefecture: Rooftop tree-planting.
5) Work to improve FW draining on a golf course (Super Sol).
6) Vegetation project on the roof of the PHP headquarters building (Super Sol).
7) Vegetation project on the roof of an existing train depot for the Kita-Osaka Kyuko
railway Co. Ltd. (Super Sol).
Comparison with Conventional
Construction of Glass Board
Construction
Foam Waste Glass Board
Fig.4.2.1-2. Vegetation on Bedrock Slopes with the Use of Foam Glass2), 3)
[References]
1) Yu Hara, Katsutada Onizuka, Mami Sato and Setsuko Momosaki: Recycling Waste
Glass—Rooftop Vegetation Using Foam Waste Glass, Japan Society of Waste
Management Experts, 12th Symposium of the Japan Society of Waste Management
Experts Thesis Collection, pages 469 to 471, 2001.
2) Yu Hara, Katsutada Onizuka, Atsuyoshi Eguchi and Mami Sato: Recycling Waste
Glass—Construction Method of Slope Vegetation Using Foam Waste Glass, Japan
Society of Waste Management Experts, 11th Symposium of the Japan Society of Waste
Management Experts Thesis Collection, pages 483 to 485, 2000.
3)
Yu
Hara,
Katsutada
Onizuka,
Mami
256
Sato
and
Setsuko
Momosaki:
Environmentally-Friendly Examples of Constructing Vegetation on Slopes—Vegetation
Construction Using Foam Waste Glass, Japanese Geotechnical Society, Soil and
Foundations, Vol.49, No.10, pages 13 to 15, 2001.
4) Yu Hara, Katsutada Onizuka, Mami Yokoo and Setsuko Momosaki: Slope vegetation
Method by the Use of Foam Waste Glass, Japanese Geotechnical Society, Soil and
5) Editorial Committee, Encyclopedia of New Environmental Management Technology
and Equipment,: Waste Processing and Recycling, Industrial Research Center of Japan,
Encyclopedia Publication Center, Pages 176 to 179.
6) Third of series “Forefront of Recycling Beverage Containers: Activities of the Japan
Glass Bottle Association”, Cities and Waste, Vol.31, No.10, 2001.
Purposes, December 2000.
4.2.2 Spring Water Processing Materials
Planting vegetation in areas with lots of spring water leads to such problems as root rot
and the vegetation base material being peeled off or washed away. Foam waste glass is
an effective method of processing spring water.
To conform to the stipulations laid down in 4.2.1 (1), Chapter 3.
There is an example of it being used on an excavated incline where there is spring water.
Two previous attempts were made to cover the incline with vegetation base material, in
order to grow vegetation. The problem of the soil material being stripped and washed
away by the spring water fed by heavy rain, led to the use of foam waste glass as a
spring water processing material and the environment for growing vegetation was
subsequently improved.
Foam waste glass and local soil were packed in sandbags and placed in a cast-in-situ
shotcrete framework in order to increase spring water drainage capabilities. As a result,
the glass packed in the sandbags absorbed and retained the water and then fed it to the
vegetation base material in which the vegetation was planted. The use of foam glass as
an isolating material is especially good for spring-water processing during rainfall and
it has great potential for preventing soil erosion on slopes caused by spring water and as
a vegetation base that can be used with other vegetation base materials.
257
Vegetation Growth After
Incline After Spring-Water Processing
Processing
Sandbags Containing Foam Glass Set in Concrete Framework
Fig. 4.2.2-1. Spring-Water Processing Material Using Foam Waste Glass1),2)
[References]
1) Yu Hara, Katsutada Onizuka, Atsuyoshi Eguchi and Mami Sato: Recycling Waste
Glass—Slope Vegetation Using Foam Waste Glass, Japan Society of Waste
Management Experts, 11th Symposium of the Japan Society of Waste Management
Experts Thesis Collection I, pages 483 to 485, 2000.
2)
Yu
Hara,
Katsutada
Onizuka,
Mami
Sato
and
Setsuko
Momosaki:
Environmentally-Friendly Examples of Vegetation Construction on Slopes—Vegetation
Construction Using Foam Waste Glass, Japanese Geotechnical Society, Soil and
3) Yu Hara, Mami Yokoo, Atsuyoshi Eguchi and Setsuko Momosaki: Examples of
258
Constructing Vegetation on Slopes Using Foam Waste Glass—Foam Glass as Spring
Water Processing and Water-Retention Material, Japanese Geotechnical Society,
Forum on Evaluating Environments that Take Ecosystems into Consideration in Soil
Engineering (2nd), pages 43 to 48, 1999.
4.2.3 Foundation Improvement Materials
There are examples in which foam waste glass was used as a stabilization admixture in
the deep layers of weak soil foundations, in the shallow layers of road-bed soil and to
provide drainage in order to accelerate consolidation.
Soil improvement with the use of lime or cement is usually carried out on silt clay or
other types of weak road-bed soils that have high levels of initial water content. There
are examples of foam waste glass being used as improvement material, in addition to
lime and cement (see Fig.4.2.3-1.)
Excellent improvement effects can be obtained when lime or cement is used
independently. On the other hand, it is possible to reduce the amount of lime or cement
in admixtures. This is achieved thanks to the synergistic effect of foam glass lowering
water content by initiating dehydration through reaction with the lime or cement and
the water absorption capabilities of foam glass when it is used as a coarse aggregate.
The water absorption rates and dry density rates of foam glass differ, depending on the
conditions of manufacture. It is advisable to use foam waste glass products with
relatively low levels of water absorption when it is used for soil improvement purposes.
Fig.4.2.3-1. Soil Improvement Effects with Different Initial Water Content Rates1), 2)
259
[Examples of Usage]
- Hado region, Chinzei-cho, Higashi-Matsuura-gun, Saga Prefecture: Road construction.
[References]
1) Katsutada Onizuka, Mami Yokoo, Yu Hara and Shigeki Yoshitake: Engineering
Characteristics and Examples of the Effective Use of Foam Waste Glass, Japanese
Geotechnical Society, Soil and Foundations, Vol.47, No.4, pages 19 to 22, 1999.
2) Shigeki Yoshitake, Katsutada Onizuka, Yu Hara, Kazuaki Ochiai and Hiroyuki
Okabe: Improving Weak Road-Bed Soil by Use of Waste Glass, 33rd Japanese
Geotechnical Society Research Seminar, pages 2521 to 2522, 1998.
4.2.4 Lightweight Aggregate
Of the different types of foam waste glass available, the type with an independent gap
structure providing high levels of drainage is light in weight, has excellent heat
insulation capabilities and is extremely strong. There are examples of foam waste glass
with these characteristics being used as a lightweight aggregate in secondary concrete
products to manufacture sound-proofing and heat-retention materials. When foam glass
aggregate is subjected to preventative countermeasures against alkali aggregate
reaction and then used for secondary concrete products, the weight of the products can
be reduced. Not only can it be used for manufacturing lightweight concrete, but it is also
suitable as an aggregate for lightweight asphalt.
Permeable Paving Slabs
Lightweight Aggregate
Using Lightweight Aggregate
260
Fig.4.2.4-1. Lightweight Aggregate Using Foam Waste Glass5)
Table 4.2.4-1. Properties of Lightweight Foam Waste Glass Aggregate5)
Water
Particle
Point Load
Thermal
Unit Weight
Absorption
Product
Size
Strength
Conductivity
(kg/1)
Rates 24h
(mm)
(kgf)
(kcal/mh℃)
(%)
No.1
Less than
0.38 to 0.48
1 to 2
10 or less
1.2
No.2
1.2 to 2.5
0.29 to 0.42
3 to 5
10 or less
0.086
No.3
2.5 to 5.0
0.26 to 0.38
3 to 7
10 or less
3M
Less than
0.36 to 0.47
1 to 7
10 or less
5.0
Table 4.2.4-1. Chemical Properties of Lightweight Foam Waste Glass Aggregate2)
(mass%)
Ig.loss
SiO2
Al2O3
Fe2O3
MgO
CaO
Na2O
K2O
SO3
1.3
68.2
6.3
0.6
0.6
9.5
11.7
1.3
0
[Examples of Usage]
1) Construction of the 2nd Annex to Osaka Gakuin University (lightweight aggregate,
Super Sol).
[References]
1) Clean Japan Center: List of Technical Information on Waste Recycling (Revised
Industrial Waste Edition), pages 231 to 232, March 2001.
2) Toru Yamamoto: Development of Ultra Light, Super Strength, Low Absorption Waste
Glass Aggregate, Green Japan, No.139, pages 26 to 28, 2001.
3) Yu Hara, Katsutada Onizuka, Mami Yokoo and Isao Yasuda: Recycling Waste
Glass—Use in the Field of Construction 10th Symposium of the Japan Society of Waste
Management Experts Thesis Collection, pages 445 to 447, 1999.
4) Mami Yokoo, Yu Hara and Tatsuo Ishikawa: Basic Research into Lightweight
Concrete that Uses Foam Waste Glass, Japan Society of Civil Engineers, Symposium on
the Effective Use of Concrete and Resources, pages II-85 to 92, 1998.
261
5. Waste Rubber (Waste Tires)
Overview of Waste
1.4 Million tons of waste tires were generated in 2003 and 87% of them were recycled.
Waste rubber and waste tires are generally used as paving materials, paving blocks and
tiles for use on roads and as material for creating parks and recreation areas. There are
two methods in which waste tires can be adapted for use: the first is turning them into
materials which can be used on-site without other processing, (material recycling) and;
the second is to use them as a base material in factories (product recycling.) The
advantages, disadvantages and points for consideration regarding these methods of
usage are listed in Table 5-1.
Table 5-1. Points for Consideration Relating to the Use of
Waste Tires in Factory-Produced Products
Method of Usage
Advantage
Disadvantage Points
for
Consideration, etc.
Material
Recyclin
g
Recycle
d
Rubber
Reused
as Large
workability
reductions
compound
No
advantages
Rubber
Possible to utilize Large
Crumb
the
elasticity
rubber.
of reductions
physicality
processed rubber
compound.
into various shapes.
Can
be
Expensive.
Recycling
Recycle
d Tires
in
improved rubber for physicality
Used as rubber
Product
Difficult to use in tires.
Can
be
purposes
cost
tires
used
other
with
for
than
improved
processing workability.
Potential for increased
in demand.
as Increased usage possible
if
technology
improving
for
surface
processing is developed.
Can be recycled as Difficult
tires.
Cost
to The sale of recycled tires
expect increased
for use on passenger
demand.
advantages
vehicles
has
low
available.
potential.
The five different technologies available for recycling waste tires are shown in
Table 5-2.
262
Table 5-2. Methods of Recycling Tires1)
Recycling Method
Form
(1) Material Recycling
a.
Open:
The
Main Uses
Rubber
material
Railway track pads, protective work
is Crumb
mats,
rubber
pavement
material,
broken down and separated
rubber blocks, anti-freeze paving, and
and then used as the base
water-permeable pavement material.
material for other products
Recycled
Belts, hosepipes, rubber tiles, rubber
Rubber
construction-related products.
b: Closed: The material is Rubber
crumb
broken down and separated
Rubber
compounds,
such
as
agricultural tires, etc.
and then recycled for use as Recycled
the
base
material
for
the Rubber
product of same type.
(2) Product Recycling: Recycled Original
form
in order to extend the life of
Remolded tires.
the product.
(3)
Chemical
Recycling: Gas, carbon Fuel, compound agent, absorbent.
Material returned to a low black,
molecular state through heat activated
decomposition and chemical carbon
decomposition.
(4) Thermal Recycling: Used as Cut, original Fuel for cement, fuel for refining
thermal energy.
form
metal, boilers, power plants, etc.
(5) Original Form: (Used for Original
other purposes.)
Fenders,
form
fish
shelters,
landfill,
playground apparatus, etc.
(1) to (3) are also known as processed usage, (4) is also known as thermal usage, and
(5) is also known as original form usage.
263
Examples of the use of waste rubber and waste tires in park creation are explained in
2) of the Reference and these include use on lawns, use in artificial turf double-layer
permeable rubber-chip mats laid on the ground, shock-absorbing playground safety
mats, and weed-prevention sheets, etc.
[References]
1) Japan Automobile Tire Manufacturers Association: Tire Recycling Handbook, August
2000
5.1 Crushing and Recycling Processing
(1) Overview of Processing
(1) Crushing Process (Rubber Crumb)
The most common method of producing rubber crumb is to crush them mechanically, at
room temperature. There is also another method being used in which the rubber is
frozen with liquid nitrogen and then crushed, which is known as the freeze and crush
method. Two other method, one in which the rubber is crushed under high hydraulic
pressure and the other using a bi-axial screw extrusion machine, are also being
investigated abroad.
Small rubber crumb with particles of approximately 0.1mm can be produced with the
freeze and crush method, but the cost is high and therefore it is not widely used.
(2) Recycling Process (Recycled Rubber)
Recycled rubber is crushed (coarse crushing Æ fine crushing) waste tires from which all
fiber, steel wire and other impurities have been removed. This is then mixed with a
recycling agent (organic disulfide ester acid, etc.) and oil (aromatic oil, etc.), heated and
rolled to manufacture rolled sheets. As steel tires are commonly used nowadays, waste
steel tires are cut with beads and then put in the coarse cracker roll. Therefore, it is
crucial that all steel is completely removed.
The standards for rubber crumb are stipulated in the JIS K 6316 “Rubber crumb” and
the SRIS 0002 “Rubber crumb” standards, regulated by the Society of Rubber Industry,
Japan.
264
5.1.1-1 Freeze Suppression Pavement
This section applies to the use of waste tire rubber chips (hereinafter referred to as
rubber chips) as an additive to the asphalt aggregate used in freeze-suppression
pavements.
Freeze-suppression paving that uses rubber chips in the asphalt admixture utilizes the
elasticity of the rubber chips to break down thin coats of ice that build up on the surface of
roads and once again reveal the surface when vehicles drive over it. A certain amount of
traffic is required to get the best freeze-suppression effects on this pavement. It is
therefore necessary to carefully select the location in which it is to be constructed.
Modified asphalt is used in the binder, for purposes of increasing durability.
Rubber chips from waste tires are regulated by JIS K 6316 “Rubber crumb” and the
Society of Rubber Industry’s SRIS 0002 “Rubber crumb” standards.
Rubber chips are granules of 5mm or less that are made by cutting or crushing used
tires and then removing other impurities from used tires, such as fiber, wire and the
like. The particle sizes of rubber crumb that are usually used, are shown in Table
5.1.1-2.
Table 5.1.1-2. Particle Size of Rubber crumb
Sieve
Mesh Percentage
Size
13.2 mm
that
passes through
100%
4.75 mm
95 to 100%
2.36 mm
30 to 50%
0.60 mm
5 to 15%
The technology used in the design of freeze-suppression pavements that use these
rubber chips is not standardized and no specific technical standards exist, but
technologies that have been awarded construction technology inspection certification
265
are generally used at the moment, depending on the condition of the construction site.
Quality verification tests on the asphalt, asphalt emulsion, coarse aggregate, fine
aggregate and filler must be implemented in accordance with the stipulations laid down
in the Guidelines for Pavement Test Methods where necessary.
for rubber chips to be added to asphalt admixture must conform to the stipulations laid
down in 3.1.1 (2) (2), Chapter 2. In other words, effluent tests on 26 substances and toxic
content tests on nine substances must be implemented in order to guarantee quality.
Ordinary quality verification tests must also be implemented on materials other than
rubber chips that are used in asphalt admixture.
(3) Technology Used
1) Amount of Rubber Chips Added
If an inappropriate amount of rubber chips are added, it will adversely affect rolling
and care must therefore be taken. Consideration must be given to the maximum
particle size, average particle size and the amount of rubber chips to be added must be
selected within a range of approximately 2% to 4% of the aggregate’s mass ratio.
2) Particle Size of Rubber Chips
The particle size of the admixture’s aggregate must be selected with a maximum
particle size of either 20mm or 13mm, depending on the thickness of the admixture
layer to be constructed. It is desirable to ensure a construction thickness of
approximately 40mm when a maximum particle diameter of 13mm is selected for the
aggregate, and approximately 50mm when a maximum particle diameter of 20mm is
selected.
When the aggregate is to be used in resurfacing on rutted roads, the surface must be
cut or leveled beforehand, in order to guarantee an even layer after construction.
3) Blending Design Procedure
Unlike ordinary asphalt admixture, it is difficult to evaluate an admixture that
contains rubber chips with the Marshall Stability test, so the amount of design asphalt
required must be calculated from the gap ratio, etc.
The blending design procedure for an admixture that contains rubber chips is shown in
Fig.5.1.1-1.
266
Selection of maximum aggregate particle diameter
Material selection (asphalt, aggregate, filler, rubber
b )
Decision on aggregate blending
Selection of maximum aggregate particle diameter
Creation of a common Marshall sample
Design asphalt volume based on the Marshall value
Confirmation of dynamic stability, abrasion loss (when
Fig.5.1.1-1. Blending Design Procedure
4) Admixture Production
The rubber chips are inserted after the addition of aggregate during the dry mixing
stage. The mixing temperature must be calculated from the viscosity of the asphalt and
a temperature curve within a range that does not exceed 185 degrees Celsius and when
modified asphalt is to be used, it is determined based on the conditions provided by the
asphalt supplier.
The production procedure for the admixture is shown in Fig.5.1.1-2. The amount of time
that the admixture is mixed for is approximately ten to twenty seconds longer than
when mixing an ordinary asphalt admixture, which reduces productivity by
approximately 30%.
267
Aggregate inserted Å (dry mixing)
Rubber chips inserted Å (dry mixing)
Modified asphalt sprayed Å (dry mixing)
Extraction
Fig.5.1.1-2. Production Procedure of Admixture
5) Transportation
It is necessary to establish measures to prevent the temperature from dropping when
an admixture containing rubber chips is being transported. Temperature management
is also important when rolling is being carried out on admixture that contains rubber
chips during construction and temperature management to prevent temperature drops
must be implemented. It is also necessary to consider methods to prevent the admixture
from separating during transportation.
6) Construction
Construction methods must conform to the same methods used for ordinary asphalt
pavement. Because the admixture contains rubber particles that provide elasticity, care
must be taken during rolling. Rolling must be performed with a road roller in the
breakdown rolling and then the second rolling, as a finish rolling, is to be carried out
with a vibration roller (or a horizontal vibration roller) or a tire roller while the amount
of water sprayed by the rollers should be kept to a minimum.
Regulation of rubber crumb is stipulated by JIS K 6316 “Rubber crumb” and the Society
of Rubber Industry’s SRIS 0002 “Rubber crumb” standards. However, it is necessary to
implement tests related to environmental standards, even when the material satisfies
these standards.
2) Usage Results
This type of pavement has been commonly constructed as a traffic safety measure for
roads in winter. “Surveys on the Results of Test Construction of Recycled Materials
268
Generated by Other Industries” indicates that as traffic safety measures for roads in
winter, pavements of this kind are often constructed.
3) Supply
Approximately 100,000 tons of rubber crumb are recycled every year, so there are no
problems with supply. The rate of recycling waste tires stands at approximately one
million tons overall, but currently the percentage used for pavements is small.
Therefore, there appears to be no problem in increasing demand in the future.
4) Repeated Use
It is necessary to take special care to avoid overheating the admixture when it is mixed
in factories. When asphalt admixture that contains rubber chips is to be reused, it is
heated with a drier or the like and mixed at high temperatures, which may lead to the
emission of toxic gas or the release of bad odors, so it is necessary to avoid using
temperatures that are higher than the melting temperature of the rubber during factory
mixing.
5) Economic Viability
The cost of using recycled materials is cheaper than the cost of using new materials.
6) Necessity
The amount of waste tires being recycled amounts to approximately one million tons
overall and using this in pavements is an extremely effective method of reuse. Although
there are many other fields in which recycled rubber can be used: foam and effective use
of used tires in the field of construction is attracting much attention.
As electricity is used in the manufacture of rubber crumb, slight amounts of carbon
dioxide are emitted. However, this does have the effect of drastically reducing the
amount emitted in comparison to new products.
[Reference]
1) Yoshii, Kagawa and Mitsutani: Multiple Functions of Low-Noise Pavement Mixed
with Rubber Crumb and Evaluations, 22nd Japan Road Association Seminar Thesis
Collection, 1997.
2) Ohashi, Hamaguchi and Taniguchi: Freeze-Suppression Mechanism of Rubit Paving,
20th Japan Road Association Seminar Thesis Collection, 1993.
269
3) Inaba and Katsumata: Use of Freeze-Suppression Pavement (Rubit Paving) in
Northeast Japan, 20th Japan Road Association Seminar Thesis Collection, 1993.
4) Kuriki, Masuda and Hokari: Elasticity Behavior of Admixture Composition of
Asphalt Pavement Mixed with Used Tires, 21st Japan Road Association Seminar Thesis
Collection, 1995.
5) Mohri, Kumode and Fujino: Examples of the Construction of Asphalt Admixture
Using Waste Tire Chips, 21st Japan Road Association Seminar Thesis Collection, 1995.
6) Taniguchi, Inaba and Ohashi: Mechanism and Effects of Granular Rubber
Freeze-Suppression Pavement, Road Construction, July 1995.
7) Taguchi, Hokari and Hara: Use of Used Tires in Asphalt Admixture, Pavement 30-3,
1995.
8) Japan Automobile Tire Manufacturers Association: Tire Recycling Handbook, August
2004.
5.1.1-2 Porous Elastic Pavement
This section applies to attaching granular or fiber rubber chips to the surface of a
pavement with urethane resin to produce porous elastic pavements. Porous elastic
pavement blocks are pressure-molded in factories.
Porous pavement joined with urethane resin is applied to elastic pavements, the main
object of which is to reduce noise. As this type of pavement has air voids of 35% or more,
it also has a water-permeable function. Large-scale test constructions have shown that
porous elastic pavement is very effective in reducing noise, compared to drainage
pavement.
Rubber chips are made into granules or fiber by cutting up or crushing used tires and
then removing all fiber, wire and other impurities.
Rubber chip fibers with a diameter between 1mm and 2mm are used. Rubber chips from
waste tires are regulated by the JIS K 6316 “Rubber crumb” standards, but no JIS
“Rubber crumb” standards exist for fiber. Also, as quality standards for technology
relating to pavements that use these products have not become generalized, no official
technical standards exist and the specifications created by the purchaser in accordance
with requirements are used instead.
270
The environmental safety standards, test methods and safety management methods for
waste tire rubber chips must conform to the stipulations laid down in 3.1.1 (2) (2),
Chapter 2. No environmental safety standards exist for high-molecular organic recycled
materials at the moment, so effluent tests on all 26 substances and toxic content tests
on all nine substances must be implemented.
3) Aggregate, etc.
The same quality verification tests used for ordinary materials are to be used for the
aggregate and other materials used in asphalt aggregate. These quality verification
tests must be implemented in accordance with the stipulations laid down in the
Guidelines for Pavement Test Methods, if necessary.
(3) Technology Used
1) Manufacture of Paving Blocks
Rubber chips or fiber are pressure-molded into blocks together with urethane resin in
factories, to produce material from the pavement. There are examples of blocks with a
size of 1m x 1m and a thickness of between 2cm and 5cm being manufactured.
2) Construction
The manufactured block-shaped rubber pavement materials are attached to the surface
of roads with an epoxy adhesive.
No environmental standards currently exist for the reuse of rubber (waste tires). It is
therefore necessary to conform to environmental safety in accordance with the
instructions laid down in 4.1.1 (2) (2), Chapter 2.
Rubber crumb is regulated by JIS K 6316 “Rubber crumb” and the Society of Rubber
Industry’s SRIS 0002 “Rubber crumb” standards, but no standards exist for rubber
fiber.
The JIS K 6316 “Rubber crumb” and the Society of Rubber Industry’s SRIS 0002
standards are categorized into tire type and crushing method, so quality can be
guaranteed by applying these standards. As there are no standards available for
rubber fiber, it is necessary to verify the quality levels of the rubber fibers using
standards for rubber crumb before they are used.
3) Usage Results
Test constructions of roads using this material have recently been carried out as
271
“noise-reduction pavement”. Surveys on the “Results of Test Construction of Recycled
Materials Generated by Other Industries” indicate that test constructions, for the
purpose of reducing noise levels, are being implemented.
4) Supply
Approximately 100,000 tons of rubber crumb is recycled every year, so there are no
problems with supply. The amount of recycled waste tires stands at approximately one
million tons overall and as the percentage used for paving is small at the moment, there
appears to be no problem in increasing demand in the future.
5) Repeated Use
It is difficult to reuse products that contain urethane resin or other kinds of hardening
resin as the binder. It is difficult to separate the binder from the rubber when products
that use urethane resin, or other hardening resin, are recycled, so this is not a viable
option.
6) Economic Viability
The cost of using recycled materials is lower than newly manufacturing materials. Note
that, although cost reductions can be achieved by using rubber crumb instead of
manufacturing new products, the cost of the rubber crumb is relatively high in
comparison to the cost of ordinary pavements when it is used as an additive. Therefore,
this leads to cost increases over ordinary pavements.
7) Necessity
The amount of waste tires recycled amounts to approximately one million tons overall.
Although there are many other fields in which recycled rubber can be used, foam and
effective use of this in the field of construction is attracting much attention.
As electricity is used in the manufacture of rubber crumb, slight amounts of carbon
dioxide are emitted. However, it does have the effect of drastically reducing the amount
emitted in comparison to new products.
[References]
1) Meiarashi and Kubo: The Durability and Noise-Reduction Levels of Porous Elastic
Pavement—Understanding its Characteristics with Basic Measurements, Japan
Society of Civil Engineers 49th Annual Academic Seminar, 1994.
272
2) Seishi Meiarashi: “Porous Elastic Road Surface as Urban Highway Noise Measure”,
Transportation Research Record, Journal of Transportation Board No.1880, Energy and
Environmental Concerns, pp 151 to 157, 2004.
3) Toshiaki Fujiwara, Seishi Meiarashi, Yoshiharu Namikawa and Masaki Hasebe:
“Reduction of Equivalent Continuous A-Weighted Sound Pressure Levels by Porous
Elastic Road Surfaces”, Applied Acoustics Vol.66, pp751 to 887, July 2005.
5.1.1-3 Pedestrian Rubber Pavement
This section applies to the use of used rubber in pedestrian rubber paving produced
from a mixture of rubber chips and resin binder.
Wet-hardening single-drop or double-drop urethane resin with good weathering
capabilities and excellent binding capabilities must be used as the resin binder.
Either colored or transparent urethane resin may be used.
Waste tires crushed into granules with a diameter of between 0.5mm and 5mm are used
for the rubber chips. Granulated ethylene-propylene copolymer rubber (EPDM) may
also be used to add color.
Rubber chips from waste tires must conform to the stipulations laid down in JIS K 6316
“Rubber crumb”. The physical properties of all other chip materials must also conform
to these standards. The performance conditions of rubber chips that contain EPDM
must conform to the same performance conditions as ordinary rubber chips.
for rubber chips must conform to the stipulations laid down in 3.1.1 (2) (2), Chapter 2.
In other words, effluent tests on twenty-six substances and toxic content tests on nine
substances must be implemented in order to guarantee quality.
3) The quality verification tests implemented on materials other than rubber chips must
conform to the stipulations laid down in the Guidelines for Pavement Test Methods in
accordance with necessity.
(3) Technology Used
1) Admixture Production
In the case of non-permeable pavements, resin binder and rubber chips with small
particle diameters are mixed into a paste and then spread on the road surface.
273
In the case of permeable pavements, the rubber chips are stuck together with a resin
binder, so that gaps remain between the chips.
2) Pavement Structures
Rubber chip pavement is applied in a thin layer, and this is usually constructed on top
of asphalt pavements or concrete pavements.
Cross-sectional views of the structures of non-permeable and permeable elastic rubber
chip pavement are shown in Fig 5.1.1-3 and Fig. 5.1.1-4 respectively.
Fig.5.1.1-3. Cross-Sectional view of an Elastic Rubber Chip Pavement Structure
(Non-Permeable)
Fig.5.1.1-4. Cross-Sectional view of an Elastic Rubber Chip Pavement Structure
(Permeable)
274
3) Blending
When wet-hardening urethane resin is used, resin gel that forms a skin or gelatinous
material on its surface must not be used.
If the mixer or aggregate gets wet, it must be dried before use.
The amount of admixture to use must be the amount that can be consumed within the
working time.
4) Construction
Rubber chip pavement has excellent elasticity qualities and is generally constructed to
a thickness of between 0.7cm and 2.5cm. The points to be remembered during
construction are listed below.
(A) It is necessary to implement a thorough investigation into whether or not
construction is possible in consideration of the moisture content of the road surface, the
prevalent climate and temperature and the amount of time available. Construction
should be avoided when it rains and when the ambient temperature is 5 degrees Celsius
or below.
(B) Beware of the use of naked flames during construction and make sure that the
thinner is strictly controlled.
(C) Blending must be carried out immediately prior to use and the material must not be
mixed and stored for later use.
(D) When constructing this pavement for the first time, asphalt pavements must be left
to stand for at least two weeks and concrete paving also for two weeks (at least four
weeks during cold periods) before construction, in order to prevent peeling.
(E) Rolling is to be carried out by pressing down with a tamper, etc., and not with
excessive loads. Rolling is to be finished evenly with the use of a heating roller or other
machine.
1) Details on environmental safety, physiochemical properties, supply, repeated use,
economic viability, necessity and carbon dioxide emissions are the same as those
already described in 5.1.1-2, Chapter 3.
2) There are results of pedestrian pavements and the like being constructed. Pedestrian
pavements are constructed as a type of pavement that reduces stress on the knees, but
there are not very many examples of actual construction.
275
3) There are cases where the rubber chips flake away or peel off with water-permeable
paving, so daily maintenance is necessary. The size of the granules for permeable
pavements is coarser than that used in non-permeable pavements, so care must be
taken to construct it in such a way that flaking and peeling do not occur. It is also
necessary to immediately repair if any flaking or peeling that occurs, so that the
problem does not spread.
4) When fading appears in the color coat of non-permeable pavements, it is necessary to
touch them up to make sure no differences occur in the color scheme. There are cases
where color fading will appear if pigment has been used, so care must be taken during
the blending process.
5) Elasticity will generally remain unchanged, but it is necessary to investigate
methods of improving long-term durability and low-temperature construction, etc., for
rubber chips.
If reactionary high-molecular material is used as the binder, there are cases where
problems will arise with hardening unless care is taken with the temperature during
cold-climate construction.
5.1.1-4 Pedestrian Elastic Block Pavement
This section applies to pedestrian elastic block pavement that is produced by mixing
rubber chips with a resin binder and molding it into blocks.
For elastic block pavement, elastic blocks which are produced by adding crushed rubber
chips to a urethane resin binder, mixing them and putting the mixture into a mold for
heat compression molding. The size of the blocks is 30 x 30 x 2 to 3cm.
For elastic blocks, blocks made of rubber are mainly used, but some are made by
attaching rubber blocks to a concrete base material. The safety standard levels of
colored EPDM rubber, chloroprene rubber and urethane rubber are generally the same
as for ordinary rubber chips.
Rubber chips are made by crushing waste tires into granules with a diameter of
between 0.5mm and 5mm, but in addition to this, colored ethylene-propylene copolymer
rubber (EPDM,) chloroprene rubber, urethane rubber and other available rubbers are
also used.
Waste rubber tires and rubber chips are regulated by JIS K 3616 “Rubber crumb”.
276
for rubber chips must conform to the stipulations laid down in 3.1.1 (2) (2), Chapter 2.
In other words, effluent tests on 26 substances and toxic content tests on nine
substances must be implemented in order to guarantee quality.
3) The Quality Verification Tests Implemented on Materials Other than Rubber Chips
Tests must conform to the stipulations laid down in the Guidelines for Pavement Test
Methods, depending on necessity. Generally, environmental safety tests are not
required for the material used in an asphalt admixture, so the quality verification tests
are to be implemented only if deemed necessary.
(3) Technology Used
1) Pavement Structure
This type of pavement is used on pedestrian paths for which emphasis is placed on
feeling while walking. The basic structure of this pavement consists of rubber blocks
being laid on top of a foundation of an asphalt admixture or concrete layer. However,
depending on underground conditions and the product being used, there are cases
where a double-layered structure is used in which adhesive is used to stick the blocks
together partially or completely.
A cross-section of the structure of elastic block pavement is shown in Fig.5.1.1-5.
Fig.5.1.1-5. Cross-Sectional View of Elastic Block Pavement
2) Construction
On flat, even surfaces with no slopes, this type of pavement involves a partial adhesion
method of construction. A total adhesion method of construction is used on slopes. The
following points should be noted with regard to construction:
(1) The ground must be laid evenly with no undulations.
(2) Blocks made of rubber only have a tendency to expand and shrink with temperature
changes, so it is necessary to use an adhesive to stick them together partially, even on
flat, even surfaces. This is done to prevent edge curling caused by expansion of the
blocks in the summer months.
1) Details on environmental safety, physiochemical properties, usage results, supply,
277
repeated use, economic viability, necessity and carbon dioxide emissions are the same
as those already described in 5.1.1-3, Chapter 3.
2) The blocks must be replaced when they become badly damaged during use. Edges will
peel away if the adhesion to the foundation (concrete blocks, etc.,) is bad and this must
be considered during construction.
3) It is necessary to note the fact that gasoline, kerosene or the like causes rubber blocks
to expand. Rubber does not have much resistance to gasoline or other oil-based alcohols,
so care must be taken to ensure that these types of liquids do not come into direct
contact with the rubber blocks.
278
6. Waste Paper
Overview of Waste
The amount of waste paper that was recycled in 2004 amounted to 60.4% (against
53.8% in 1996) 1). In addition to recycled waste paper being used as a base material in
the production of paper, it is also used for packaging and as a base material in the fields
of public works, construction and agriculture.
6.1 Shredding and Thermal Pressure Processing
The percentage of waste paper that is used for purposes other than preparing the base
material of paper, is less than 1% (0.66% in 2004,) 1) and this is mostly used as solid fuel.
Only very little of this is recycled with thermal pressure molding (reductions have been
recorded, in fact, with approximately 5% in 1996 reducing to approximately 3% in
2000.) 1)
There are two methods available for separating the fibers of waste paper: the wet
solution fibrillation method and the dry solution fibrillation method. The method of
producing thermal pressure molded boards through dry solution fibrillation of waste
paper, to be used in concrete molds, is shown in Fig.6.1.
Fig.6.1-1. Example of the Manufacturing Processes of Waste Paper Boards
The methods of separating the waste paper fibers include the wet solution method and
the dry solution method. The basic composition of the fibers produced mechanically
after collection using the dry solution method, are shown in Table 6.1-1. In comparison
to the vegetable fibers used as the base material for manufacturing new paper, the
length of these fibers is one-third or less and the strength is one-half or less. When the
recycled material requires a certain level of strength, it is possible to cover these low
values by adding new vegetable or other fibers .
Table 6.1-1. Basic Composition of Waste Paper
279
Item
Unit
Waste Paper
Vegetable Fiber
Density
g/cm３
1.55
1.52
Maximum
µm
600
5,000
µm
300
1,100
µm
45
45
Fiber Length
Average Fiber
Length
Average Fiber
Width
[References]
1)
Paper
Recycling
Promotion
Center:
Paper
Recycling
Handbook
2005,
http://www.prpc.or.jp/kami-handbook2005/1.htm
2) Clean Japan Center: New Recycling Keywords, 3rd Edition, Economic Research
Committee, 1997.
280
6.1.1 Concrete Mold Frames
This section applies to the use of panels manufactured by molding waste paper by
thermal pressure in concrete mold frames. In addition to using waste paper alone, the
base materials for the panels includes ones blended with plastic, various binders, fibers
and/or strengthening additives. However, the mold frame must be removed after the
concrete has hardened.
The evaluation items, tests, inspection methods and verification items for concrete mold
frames are shown in Table 6.1.1-1.
Table 6.1.1-1. Evaluation Items, Tests, Inspection Methods and
Verification Items for Concrete Mold Frames
Evaluations
Dynamic
Tests & Inspections
1) Rigidity test
Major Tests and Inspection Methods
JIS A 8652 “Metal Mold Frame Panels”
Characteristic 2) Bending strength test
Bending Endurance Test
s of Panel
Endurance of 1) Water absorption test
JIS A 5905 “Fiber Boards”
Sheathing
2) Absorption thickness JIS A 5905
Board
expansion test
“Fiber Boards”
3) Wet bending strength
JIS A 5905
“Fiber Boards”
4) Alkali resistance test
Japan Agriculture Standards (JAS) for Concrete
Mold Frames
Mold
1) Un-nailing endurance
Processing
test
Capabilities
2)
until half of its length and the maximum withdrawal
Severance
and endurance is measured.
hole-drilling
Mold
A nail (N45) is driven vertically into the board up
time The product is cut in half with a saw and drilled with
inspections
a power drill.
1) On-site inspections
Checks are carried out to verify that tools used for
Usability
plywood mold can be used on-site in a similar
2)
End
inspections
product manner.
Concrete is poured into the mold, the mold is removed
after 7 days and the surface of the concrete is
inspected.
281
The quality control standards of waste paper concrete mold frames are shown in Table
6.1.1-2.
Table 6.1.1-2. Quality Control Standards for Waste Paper Concrete Mold Frames
Item
Unit
Bending
mm
Standard Value
5.0 or less
Test Methods
- JIS A 8652 Metal Mold Panels
characteristics
- Size of specimen: Length 1,800mm,
Width 900mm, Height 72mm (board
Amount of warping
thickness 12mm + woodchip 60mm)
under localized loads
- Load application: 2-point support,
2-point load, distance between supports
900mm.
Class 3 load, weight 10kN/m
Water
absorption
%
5.0 or less
JIS A 5905
“Fiber Boards”
Absorption thickness
%
1.0 or less
JIS A 5905
“Fiber Boards”
ratio
expansion
Wet
bending
N/mm２
13.0 or less
Compliant with JIS A 5905
strength1)
Alkali resistance
“Fiber
Boards”
−
Minimal
color JAS for Concrete Mold Frames
change only2)
1): Soaking time = 3 hours in 20 degree Celsius water.
2): Minimal color change only. No blistering, peeling or excessive changes in shininess.
(3) Technology Used
1) Design
It is advisable to implement the design so that it satisfies the quality standards for
concrete mold frames stipulated in Table 6.1.1-1 “Evaluation Items, Tests, Inspection
Methods and Verification Items for Concrete Mold Frames”.
2) Construction
It is advisable to confirm that the mold frames can be assembled, constructed and
dismantled using the same work methods used for plywood mold frames before
construction.
3) Repeated Use and Disposal
It is advisable to consult with the manufacturer of the mold frame when waste paper
282
concrete mold frames are to be reused, recycled, processed or disposed of.
As there is a lack of usage results, there are many cases for which the number of
times these frame molds can be used, has not been clarified. It is therefore necessary to
verify the mechanical characteristics, endurance levels, warping and surface rigidity of
the panels before deciding on the number of times they can be reused.
Mold frames that consist of waste paper and waste plastic easily peel away from
concrete and are therefore easy to dismantle, and they should not be dropped from high
locations. Preventing damage to the surface helps to increase the number of times they
can be reused. Although these panels should be stored indoors, as a basic principle, in
the event that they are to be stored outdoors, it is necessary to make sure that they are
covered with protective sheets, etc.
[Examples of Usage]
1) Underground construction frame (waste paper frames) 80m3, Municipal facility
Maintenance Division, Housing and Building Bureau, Osaka City Government, test
construction (the reuse of the panels not viable for around eight uses.)
2) Mold frame for poured concrete (waste paper + waste plastic mold frames) 3,550m2,
Kanto Regional Development Bureau Kofu Construction Office, used twice.
3) Footing mold frame for external retaining wall (waste paper + waste plastic mold
frames) 4,300m2, Kanto Regional Development Bureau Kofu Construction Office,
used twice.
[References]
1) Sanwa Construction Materials Co., Ltd.: Report on Civil Engineering Material and
Technology Inspection Certification, “Eco-Pal Panel” Concrete Mold Frames that do not
Use Plywood, Public Works Research Center, July 1997.
283
7. Waste Wood
Overview of Waste
To conform to the stipulations laid down in 4, Chapter 2.
7.1 Carbonization
When wood is incinerated in a low-oxygen environment, the organic contents are subject
to a thermolysis reaction, which carbonates the wood. Carbonizing wood has the ability
to prevent decay and provides it with the ability to absorb oil, owing to its micro-porous
structure, and be converted easily into biological slime with supplementary effects on
fine particles, etc.
7.1.1 Soil Improvement Materials
This section applies to the use of waste wood as a soil improvement material after it has
been crushed and carbonized.
Mixing this with soil helps adjust the particle size and produces lightweight soil. It also
supplements
the
water-retention
capabilities,
heat-retention
capabilities
and
self-cleansing functions of the soil and its effect of improving clay soil into a soil capable
of cultivating vegetation, is anticipated.
The environmental safety standards must conform to the stipulations laid down in 4.1.1
(2) (2), Chapter 2.
(3) Technology Used
This material is light, greatly improves the physical properties of soil (water
permeability, air permeability, water-retention, heat-retention) and prevents topsoil
from being washed away by rain. It is also expected to have a great effect in restoring
agricultural land devastated by the overuse of pesticides and chemical fertilizers, to
increase the number of microorganisms contained in the land and increase overall land
fertility. The uses for this material include the improvement of weak soil, the
improvement of clay soil, as nutrients for lawns and for joint soil, etc.
There are examples of carbonated waste wood being used by the Kanto Regional
Development Bureau and the City of Kyoto in land reclamation and as soil
improvement material for park maintenance work.
284
7.1.2 Earth Retaining Materials for Bank Protection
This section applies to the use of waste wood that has been carbonized and poured into
metal nets, which have been treated with anti-corrosives, as a substitute for gabions, etc.
The gaps between the chips provide living space that is used by vegetation and small
creatures that help to restore and maintain the natural environment. It is used as a
substitute for logs and earth-retaining materials along the banks of rivers.
The environmental safety standards must conform to the stipulations laid down in
4.1.1 (2) (2), Chapter 2.
(3) Technology Used
Natural environment improvement of rivers, lakes and marshes, regulating
reservoirs, moats, ponds in gardens, etc.
(4) Usage Results
Several examples of actual usage in construction projects exist.
7.2 Wood Meal + Plastic
The waste wood generated by construction projects and periodical trimming of the trees
and bushes that line roads in towns, etc., is ground into wood meal, mixed with
polyethylene or another type of waste plastic, pressure is then applied and the mixture
is melted and formed into the required shape.
7.2.1 Mold Frame Materials
This section applies to the use of wood meal made from waste wood to which plastic is
added and the mixture then used as mold frames.
The material used up until now for mold frames into which concrete is poured during
construction projects has consisted of plywood made from timber taken from tropical
rain forests and therefore the use of plywood is one of the factors contributing to the
deforestation of tropical rain forests, which is one of the causes on global warming. The
use of waste wood in producing mold frames, etc., is a countermeasure against this.
Mold frames made of wood meal and plastic have been developed, and this has
construction capabilities and levels of strength that are equal to those manufactured
from plywood.
285
Conforms to the standards stipulated for wooden mold frames.
It is also advisable to refer to Section Three, 6.1.1 (2), Chapter 3.
(3) Technology Used
An example of this material being used in the footing areas of bridge supports, has been
recorded in the city of Fuji, Shizuoka Prefecture (used for five of the fourteen footings,
reused five times.) 1) Although this mold has lower moisture absorption, it is heavier,
more slippery than plywood having same thickness, hard and difficult to cut. Also, as
there are very few results on the number of times these molds can be reused, it is
necessary to initiate further investigations in the future.
7.2.2 Civil Engineering Materials
This section applies to the use of wood meal made from waste wood to which plastic has
been added as a substitute for wood in public works projects.
It is necessary to confirm that they have the same or higher levels of strength than the
wood they substitute for, prior to usage.
(3) Technology Used
Examples of benches, blocks and poles being manufactured exist.
[Examples of Usage]
The results of usage between 1999 and 2002 are listed below.
1) Planks for boardwalks in parks, benches in parks, pedestrian path benches
(Kanagawa Prefecture).
2) Bridge railings in parks (Kochi Prefecture).
3) Fences and benches in a public plaza (Miyagi Prefecture).
4) Fences to prevent access to salt-injured park roads (Kanto Regional Development
Bureau).
5) Landing bridge (Kinki Regional Development Bureau).
6) Safety barriers on national roads (Shikoku Regional Development Bureau).
7) Signboards and posts in parks (Shikoku Regional Development Bureau).
Additional examples of use as wooden paving boards, roadside poles and fences, etc., are
provided in Reference (2).
286
[References]
1) The Committee for the Promotion of Recycling of Construction By-Products: Case
Study of the Tagonoura Elevated Bridge Supports on the Route 1 Fuji-Yui Bypass,
Construction Recycling, Vol.17, 2001 Fall Edition, 2001.
287
Chapter Four. Materials Requiring Future Investigation
288
1. Coal Ash
Overview of Waste
This is the same as already explained in 3, Chapter 2.
1.1. Solubilization and Solidification
The solubilization and solidification process generally consists of melting the ash
content of coal at temperatures of 1,200 degrees Celsius or higher and then cooling it
into solid matter.
A crushed-coal-burning furnace, which is generally used in coal thermal power plants or
the like, is used as the melting furnace. The combustion chamber of the PCB furnace is
equipped with fire-resistant materials to enable the coal to be burned at high
temperatures. The coal ash is melted in this furnace, and what is extracted is not ash,
but a slag that is chemically stabilized and homogenized and whose active ingredients
have been separated.
Several dozen melting furnaces of this type are being used overseas as large-scale
electricity-generating boilers, and their use has enabled a wealth of results to be
accumulated. In Germany and other countries, the slag produced by these furnaces is
thought to have no bad effects on the environment, and the slag is used in a wide range
of public works projects.
In Japan, the production of water-granulated slag has been reported at a test plant, and
the use of this slag as a finely aggregated asphalt admixture has been subject to
laboratory testing, test construction, and follow-up research1). This test ash melting
furnace-type boiler has been modified so that it can perform solubilization solidification
processing of not only ash generated in the furnace itself, but also coal ash generated in
other boilers.
289
Exhaust gas
Fine particle coal
Coal ash (circulatory ash)
Coal ash (from other boilers)
Slag tank
Conveyor belt
Water tank
Crusher machine
Vibration sieve
Fig. 1.1-1. Coal Ash Solubilization Boiler System3)
2）Physiochemical Properties
1) Composition of Molten Slag
The composition of molten coal ash slag generated in Japan is said to have a
composition similar to that of mountain sand, with the following percentages: SiO2:
64.8% (slag), 56.5% (sand); Al2O3: 21.4% and 25.3%; Fe2O3: 6.1% and 11.1%; CaO:
2.9% and 4.6%; and MgO 0.9% and 0.9%. This is approximately the same composition
as the molten coal ash slag obtained in Germany, as can be seen in Table 1.1-1. Note
that, in Germany, the composition of the slag is said to be almost the same as that of
basalt. Molten coal ash slag not only shares similar components with normal molten
incineration slag: it is also remarkably similar in external appearance and physical
properties.
290
Table 1.1-1. Composition of Molten Coal Ash Slag Produced in Germany
Component
Amount in Slag (German Coal)
(%)
SiO２
45 to 55
CaO
2 to 6.5
Al２O３
24 to 31
Fe２O３
3 to 10
Na２O
0.4 to 0.5
K２O２
3 to 5
MgO
1.1 to 3
PbO
≦ 0.1
TiO２
0.9 to 1.2
MnO
0.1 to 0.2
ZnO
0.1 to 0. 3
SO３
0.3 to 0.7
Cl
< 0.01
Other
3 to 3.5
2) Physiochemical Properties of Slag
An example of water-granulated slag generated by controlling particle size distribution
and particle form using a crushing machine is shown in Photograph 1.1-1, and the
physical properties of this slag are shown in Table 1.1-2. The results of heavy metal
effluent tests in regard to environmental safety are shown in Table 1.1-3.
Photograph 1.1-1. Water-granulated Molten Coal Ash Slag3)
Table 1.1-2. Physical Properties of Water-granulated Molten Coal Ash Slag (Compared
with Natural Sands)
291
Test Item
Slag (g/cm3)
Fine Sand
Coarse
Sand (g/cm3) (g/cm3)
Surface Dry
2.602
2.562
2.547
Bulk Density
2.598
2.524
2.553
Apparent
2.616
2.624
2.632
0.33
1.52
2.06
NP
NP
NP
4.75 mm
―
100.0
100.0
2.36 mm
100.0
96.5
94.3
600 µm
57.8
59.7
75.6
300 µm
28.3
15.3
49.6
150 µm
11.5
0.6
7.3
75 µm
5.9
0.4
2.3
Density
Density
Water
Absorption %
Plasticity
Index
Table 1.1-3. Results of Effluent Tests on Water-granulated Molten Coal Ash Slag
Incineration Coal
Effluent Test
Test Item
Soil Env. Stds
(mg/l)
Cadmium
Lead
Chrom Hexa.
Arsenic
Total mercury
Selenium
Fluorine
Boron
0.01≧
0.01≧
0.05≧
0.01≧
0.0005≧
0.01≧
(0.8≧)
( 1≧)
Det. Limit
(mg/l)
0.001
0.005
0.005
0.001
0.0001
0.001
0.1
0.05
Daido
for Test Pav.
ND
ND
ND
ND
ND
ND
ND
ND
Daido
Hunter Valley
Taiheiyo
ND
ND
ND
0.001
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
−
−
ND
ND
ND
ND
ND
ND
ND
ND
Tiger Head
ND
ND
ND
ND
ND
ND
ND
ND
Irawara
Ensham
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
ND
Results of Measurements by the Japan Food Research Laboratories
The geotechnical characteristics of the slag generated by a German slag-tap boiler (ash
solubilization boiler) are shown in Table 1.1-4. The main features of the molten coal ash
slag from this German coal are as follows.
-
The granules are vitrified.
-
The granules have a diameter of between 0 and 10 mm, and are flat with acicular
edges.
292
-
They are chemically neutral and do not adversely affect the environment.
-
When a small amount of cement is added to the slag for adjustment purposes, it is
possible to attain a compaction strength of 8 N/mm２.
-
Untreated slag deposited after it has been generated has high levels of permeability
(see Table 1.1-4.)
-
The granules are solidified through chemical reactions with lime or concrete.
-
When a load is applied, crushing occurs along the stress surfaces of the particles.
Crushing with an impact crusher reduces the surfaces that have the potential for
cracking, consequently improving particle conditions.
-
It is possible to store the slag outdoors or in intermediate silos.
Table 1.1-4. Geotechnical Characteristics of German Slag Soil
Soil Particle
2.4 to 2.6g/m3
Density
Rolling
1.3 to 1.5kg/cm３
Density
Permeability
2 to 3 x 10−３m/s
Coefficient
293
Table 1.1-5. Properties of an Admixture made from Water-granulated Molten Coal Ash
Slag
Blend Type
Admixture Blend (%)
Item/Characteristics
Slag 10%
Blend (3):
Slag 20%
35.8
35.8
35.8
No. 7 Crushed Stone
19.8
19.8
20.7
Screenings
13.2
9.4
5.7
Molten Coal Ash Slag
−
9.4
18.8
12.3
8.5
4.7
Fine Sand
8.5
6.7
3.8
Stone Powder
4.7
4.7
4.7
Asphalt
5.7
5.7
5.8
19.0mm
100.0
100.0
100.0
13.2mm
99.1
99.1
99.1
4.75mm
62.5
2.36mm
42.2
42.8
42.5
600µm
25.5
25.8
25.3
300µm
15.0
15.2
15.0
150µm
7.7
8.1
8.3
75µm
5.8
5.9
6.0
Percentage of Volume that Passes through Sieves %
Particle Size of Aggregate
Slag 0%
Blend (2)
No. 6 Crushed Stone
Coarse Sand
2.381
Density (g/cm3)
62.4
2.378
2.378
2.480
2.477
2.472
4.0
4.0
3.8
Saturation Ratio (%)
76.5
76.5
77.8
Stability Ratio (kN)
9.8
9.2
8.8
Flow Value (1/100cm)
23
23
24
Residual Stability (%)
87
87
87
Theoretical Density
Admixture Properties
Blend (1):
(g/cm3)
Air Void (%)
294
Molten coal ash slag is still at the test manufacturing stage in Japan, and thorough
investigations into its quality need to be implemented.
2) Results of Usage
Although there are many results from the use of molten coal ash slag aggregate overseas,
test manufacturing at test plants is still being carried out in Japan, and so far only two cases
of use have been reported. It is therefore necessary we operate as many ash melting boilers
as possible on a commercial basis in the same way as overseas. Molten coal ash slag is
thought to be superior to fly ash from the point of view of environmental safety. The many
results reported from abroad of its use as an aggregate and the results from the few cases
available in Japan indicate that molten coal ash slag is very similar to general molten
incineration ash slag in appearance, composition, and physical properties. Therefore, it is
thought that it can be used as a hot asphalt admixture or the like, as a substitute for natural
sand. Also, each coal-powered electric power plant produces several hundred thousand tons
of coal ash every year, and it is therefore desirable to recycle this into aggregate when the
recycling capacity for general coal ash reaches its limit.
There is no increase over conventional materials in terms of the amount of carbon dioxide
emitted when molten slag is used as an aggregate in heated asphalt. However, because it is
manufactured by melting at temperatures of 1,200 degrees Celsius or higher, more carbon
dioxide is emitted in comparison with the conventional method of producing incineration ash
from coal at temperatures of around 800 degrees Celsius.
1) Kato et al.: Use of Molten Coal Ash Slag as Fine Aggregate for Asphalt Pavement,
Pavement, March 2001
2) Inada et al.: Use of Molten Coal Ash Slag as Fine Aggregate for Asphalt Pavement,
24th Japan Road Association General Thesis Collection, October 2001
3) Kawasaki Heavy Industries, Ltd.: Pamphlet, Molten Coal Ash Slag
4) Committee for the Civil Engineering of Energy Equipment: Current Situation and
Technological Perspectives for Using Coal Ash as a Public Works Material—Backfill,
Embankment Fill, Soil Improvement, Japan Society of Civil Engineers, April 1990
5) BVK Technical Documentation: A Granulate with Many Possibilities (Steag)
295
6) Von K.-H. Puch,W. vom Berg: Nebenprodukte aus kohlebefeuerten Kraftwerken,
VGB-Kraftwerkstechnik, 1997, Helt 7
296
2. Waste Roofing Tiles and Ceramics
Overview of Waste
Waste roofing tiles and waste ceramics generated from sources other than production
plants and construction work are generally used in public works projects on their own or
mixed with other materials to make road construction materials, such as pavement
blocks or tiles.
The following examples are provided in Reference 1):
1) Paving materials used at scenic sites and as flat fake stone concrete slabs (waste
roofing tiles)
2) Recycled bricks (crushed stone waste sludge, waste roofing tiles, waste alumina
material)
3) Permeable ceramic blocks (waste ceramics)
4) Ceramic flooring blocks (waste ceramics, waste clay from the ceramics industry)
5) Permeable ceramic blocks (waste ceramics, incinerated sewage sludge ash)
6) Fired bricks (waste ceramic clay, waste ceramics from construction projects, sludge
from water supplies)
7) Fired sludge bricks (incinerated sewage sludge ash, waste ceramic pipes,
washed-away sand)
8) Permeable ceramic blocks (waste ceramics)
9) Permeable ceramic paving (iron and steel slags, waste ceramics)
10) Recycled sewage sludge blocks (incinerated sewage sludge ash, Selben (crushed
ceramics, ceramic waste factory sludge))
11) Ceramic blocks (waste ceramics, waste clay from the ceramics industry,
incinerated sewage sludge ash)
Survey results gave the following examples of the use of ceramics on roads between
1999 and 2002:
1) Flat pedestrian slabs, on the surface of which waste material was applied to (waste
glass, tiles, roofing tiles, Chiba Prefecture)
2) Pathway paving in parks (roofing tile dust, Toyama Prefecture,) water-retention
tiles (waste ceramic products, Okinawa Prefecture)
3) Interlocking paving (shards of waste ceramics, Kinki Regional Development
Bureau)
4) Subgrade material (waste roofing tiles, Kumamoto Prefecture)
5) Permeable pavement filter material (crushed tiles, Chubu Regional Development
297
Bureau)
Examples of the use of waste ceramics for purposes other than roads between 1999
and 2002 are listed below:
1) External building gutter tiles (incinerated sewage sludge ash, waste ceramics,
Yamagata Prefecture)
2) Fine aggregate for secondary concrete products (raw concrete containing waste
roofing tiles, Fukui Prefecture)
3) Weed-proof mulch (waste roofing tiles, Hokuriku Regional Development Bureau)
[Reference]
1) Construction Research Institute: Handbook on Recycled Materials Used in
298
3. Seashells
Overview of Waste
The amount of waste generated by the fishing industry in Hokkaido alone is between
400,000 and 50,000 tons per year, and, of this, scallop shells account for approximately
187,000 tons (fiscal year 2002.) 1) Reduction and recycling are consequently important
topics that need to be addressed.
The Ministry of Land, Infrastructure, and Transport’s Tohoku Regional Development
Bureau has compiled guidelines2) on the effective use of molten slag, incineration ash
(clinker ash), and oyster shells. These guidelines confirm the fact that seashells, the main
constituent of which is calcium, can be used without prior treatment as a substitute for
sand mats. In tests on embankment fill it was also confirmed that seashells have similar
settlement to sand and are easy to use.
Recycling and reuse of seashells are mostly carried out in Hokkaido. Examples of usage
recorded for the period 1999 to 2002 are as follows:
1) Freeze-suppression material on roads (at a terminal for snow-clearing vehicles) (scallop
shells, Hokkaido)
2) Filler for asphalt paving construction (scallop shells, Hokkaido Regional Development
Bureau)
3) Water-decontamination material (scallop shells, Hokkaido Regional Development
Bureau)
4) Culvert coverage (scallop shells, Hokkaido Regional Development Bureau)
5) Center-fill for soil improvement work (scallop shells, Hokkaido Regional Development
Bureau)
6) Pedestrian path tiles (scallop shells, Hokkaido Development Bureau)
7) Aggregation material for adhering grains of dredged soil and improving dehydration
efficiency (scallop shells, Hokkaido Regional Development Bureau)
8) Soil improvement material (scallop shells, Hokkaido Regional Development Bureau)
9) Weed-proof pavement in planting zones and traffic islands (oyster shells, scallop shells,
Hokkaido Regional Development Bureau)
1) Hokkaido Fisheries Division: Fiscal Year 2003 Survey on Waste Produced by the
Fisheries Industry (covering Fiscal Year 2002), March 2004
2) Ministry of Land, Infrastructure, and Transport, Tohoku Regional Development
Bureau, Technology Development Committee Aiming at Zero Emissions, Committee of
299
Experts on Technology for Using Waste and Molten Slag: Guidelines for Using Seashells
as a Substitute for Sand Mats (proposed), March 2003
300
4. Waste Plastics
Overview of Waste
The production volume of plastics was 100,000 tons/year in 1955, and it peaked at 15.2
million tons/year in 1997. Since then, the volume has begun to drop, but even with these
reductions, 13.85 million tons were produced in 2002.
The total generation of waste plastic has leveled out in recent years, with 9.9 million
tons in 2002, and the effective use of this waste is showing a tendency to increase, with
Category
Type
Application
Polyethylene terephthalate
PET bottles, tapes, films
Thermoplastic High-density polyethylene
Kerosene containers, bottles, nets
s
Polyvinyl chloride
Egg cartons, plastic wrap
Low-density polyethylene
Polythene bags, communication cables,
lids
Polypropylene
Bathtubs, automobile parts, injections
Polystyrene
Cabinets, trays, toys
Other thermoplastics
Ball-point pen holders, signboards,
feeding bottles
Thermosetting Heat plasticity Plastic
Buttons, kitchenware, yacht hulls
Plastics
5.42 million tons recycled in 2002 (55%)1).
Waste plastic is used in a variety of applications, depending on its composition, as can
be seen in Table 4-1.
Table 4–1. Plastic Types and Uses2)
Waste plastic is classified into two major categories; industrial waste plastic and waste
plastic extracted as general waste. The amount of plastic generated as general waste
greatly surpasses that generated as industrial waste, and this creates many problems
with regard to processing and disposal. The separation and recycling of waste plastic have
therefore been regarded as important issues from the viewpoint of reducing waste
volumes and recycling resources. However, various different types of plastic are mixed
together even when plastics are separated, and the contents are also often contaminated
301
with food residues, etc., so even though plastics recycling is technologically available,
there still exist many problems such as economic viability and potential application.
Because separating the plastic generated as industrial waste is a relatively simple task,
recycling it is also comparatively easy. However, as processing technologies and recycling
systems differ depending on the condition in which the waste plastic is submitted, the
development of an economically viable collection system remains a major problem.
[References]
1) Plastic Waste Management Institute: 2004 Basic Knowledge of Plastic Recycling.
2) Saburo Nakamura: Introduction to Visual Ecology—Recycling Systems, Nippon
Jitsugyo Publishing, September 1998
4.1. Crushing and Recycling Processing
The technologies available for recycling waste plastic are as follows:
1) Material Recycling
(1) Crushing and simple recycling (material recycling)
Waste plastic of good quality generated during the product-processing stages (waste,
leftover, and defective plastic that can be sorted by resin content and by color) is
crushed, recycled into pellets or granules as a material for remolding in granular form.
It is then heat molded to form new products. Thermoplastic is used for this, and the
most common plastics used are those generated from industrial waste.
(2) Crushing and compound recycling (product recycling)
The waste plastics generated through manufacturing, processing, and distribution
process that are not suitable for simple recycling are solubilized and solidified and then
formed directly into poles, stakes, and other products. Polyethylene, polypropylene,
polystyrene, and other thermoplastics are crushed in accordance with their resin
content, blended into a fixed mixture ratio, melted and kneaded, and then formed into
products. The products they form include poles, stakes, boards, public works
construction materials, packaging and transportation materials, and agricultural and
fishing-related materials.
2) Chemical Recycling
This technology returns the waste plastic to monomers and oligomers (intermediates of
polymeric polymerization) by thermal decomposition and depolymerization. Monomers
have been collected from acryl resins and polyester. Manufacturing processes for
302
polyamides have also been developed, so it is now possible to perform chemical recycling
on polyurethanes.
3) Thermal Recycling
This technology involves the use of waste plastic not suitable for recycling as a
substitute fuel for heavy oil and coal, instead of just incinerating it. The thermal energy
produced during the incineration process is converted to steam or electric power. This
manual concentrates on items (1) and (2) described in 1) Material Recycling.
The degree of deterioration in the plastics used for sales packaging, packaging for
distribution, automobiles, electronic parts and appliances and construction materials,
etc., differs depending on the environment in which they are used. They are usually in
worse condition than new products, and this makes it difficult to recycle them for use as
they are.
Moreover, in the case of wallpapers and carpet tiles, paper or fiber is mixed in with the
plastic, and the plastic used in automobiles, electronic parts, and appliances tends to be
painted or have bolts in it for attachment to metal parts, so it is necessary to separate
the plastic from these other components in order to recycle them.
Other materials are added to the plastic when the plastic is subject to material recycling
or chemical recycling, and products are manufactured in accordance with the
performance level of the recycled material, making it possible to overcome the problem
of performance deterioration caused by recycling.
303
4.1.1. Materials for Improvement of Asphalt Pavement
1) As asphalt admixtures are mixed at high temperatures, we need to investigate whether
any toxic gases are emitted in relation to the decomposition process or the characteristics
of the recycled admixture to which the waste plastic is added. Although most plastic
generated from industrial waste is sorted into types, plastics from general waste tend to
include various types, meaning that it is highly likely there will be fluctuations in
material quality when the plastic is mixed and melted with asphalt. Therefore, there is
also a high possibility that the product’s usefulness as a binder improvement material
will be restricted.
2) It is necessary to pay close attention to compatibility, affinity, and low-temperature
brittleness in relation to the asphalt or aggregate when a new thermoplastic is used as an
improvement material, and the same applies in cases where waste plastic is used.
3) The results of tests on the performance of asphalt binder mixed with fine fiber
reinforcing plastic (FRP) powder and thermoplastic indicate that, in many cases, the
thermoplastic that is melted during mixing separates from the asphalt after it has been
cooled. Certain types do not melt at all, and these are thought to be the types that do not
cause changes in the performance of the binder.
Also, the results of tests on admixture properties show a tendency for the compaction
density values and Marshall stability values to be lower for admixtures to which FRP
powder and rubber crumb have been added.
[Examples of Usage]
There are many examples of usage available, and these are listed in References 1) to 4).
[References]
1) Technology Committee, Japan Modified Asphalt Association: Surveys into the Current
Condition of Waste Plastic and its Use in Paving (No. 1), Modified Asphalt No. 3, 1994
Condition of Waste Plastic and its Use in Paving (No. 2), Modified Asphalt No. 4, 1995
3) Nishimura and Sakamoto: Tests on Asphalt and Admixture Blended with Recycled
Plastic/Recycled Rubber, Japan Society of Civil Engineers 50th Annual Academic
Seminar, September 1995
304
4) Kamata, Inaba, and Yamada: Rheological Properties of Asphalt Admixture Containing
Plastic Granules, Japan Society of Civil Engineers 49th Annual Academic Seminar,
September 1994
4.1.2. Aggregate for Asphalt Paving
1) There is a risk of toxic gas being emitted when the aggregate is mixed at high
temperatures with dryer heat, so care must be taken.
2) When waste plastic aggregate is added to pavement, it is possible that the pavement
will have insufficient strength. Therefore, it is also necessary to add other supplementary
materials, hardening agents, or the like.
3) It has been reported that it is impossible to decide on the optimum amount of asphalt
and that the effect of the additives is deficient in the case of asphalt admixtures that use
pellets, granules, or crushed-stone-type waste plastic. Under current circumstances,
waste plastic is crushed into granules with an approximate size of 5 mm and used as part
of the aggregate. It is therefore necessary to initiate investigations into the uses and
usability of such plastics.
4) Plastic is not resistant to ultraviolet rays. Its use on road surfaces may lead to cracking
and weakening owing to deterioration, so it is necessary to give full consideration to the
use of waste plastic in surface courses.
5) When plastic granules are mixed into the asphalt, it is necessary to consider the effects
that partial melting of the plastic will have on the asphalt’s performance. Plastic becomes
soft at between 120 and 130 degrees Celsius, and as a considerable portion of the plastic
in the admixture is melted during mixing, this greatly affects the performance of the
asphalt. There are also cases in which this will affect the mixing and construction
processes.
6) The results of test constructions show that although the levels of evenness are
favorable, asphalt made with plastic admixtures lacks luster in comparison with asphalt
made with ordinary admixtures. There is also a tendency for hairline cracks to appear
during rolling. It is therefore necessary to examine the use of plastic admixtures from the
viewpoint of usability and finished condition.
7) When waste plastic is used in slab form as aggregate, an additional cost for processing
the slab into pieces of granules arises, making it substantially more expensive than the
305
aggregate available on the open market. It is therefore necessary to take into account
measures for lowering processing costs, the quantity of waste plastic generated, and
social requirements.
[Examples of Usage]
Examples of usage are listed in References 1) to 11).
[Reference]
Condition of Waste Plastic and its Use in Pavement (No. 1), Modified Asphalt No. 3, 1994
Condition of Waste Plastic and its Use in Pavement (No. 2), Modified Asphalt No. 4, 1995
3) Nishizaki, Sakamoto and Nitta: Property Tests on Asphalt that Uses Waste FRP, 22nd
Japan Road Association General Thesis Collection, 1997
4) Matsushima, Mitsutani and Kataoka: Properties of Asphalt Admixture Mixed with
Waste Plastic Aggregate, 21st Japan Road Association General Thesis Collection, 1995
5) Shishido, Yokohiki and Sakamoto: Follow-up Surveys into Paving Containing Waste
Plastic, 22nd Japan Road Association General Thesis Collection, 1997
6) Yamada, Wada and Mitsutani: Use of Asphalt Paving Mixed with Waste Plastic
Aggregate, 22nd Japan Road Association General Thesis Collection, 1997
7) Kamata and Yamada: Dynamic Stability Levels and Number of Fatigue Damage Cases
in Plastic Asphalt Admixture, 21st Japan Road Association General Thesis Collection,
1995
8) Shishido, Sakamoto and Yokohiki: Use of Waste Plastic in Asphalt Admixture, 21st
Japan Road Association General Thesis Collection, 1995
9) Mitsutani: For Practical use of Waste Plastic as Pavement Material, Road Construction,
August 1996
10) Yamada and Inaba: Use of Waste Plastic as Asphalt Admixture Material, Pavement,
Vol. 29, No. 7, 1994
11) Sugawara, Sakamoto and Matsushita: Use of Waste Plastic in Asphalt Admixture,
Road Construction, September 1997
306
4.1.3. Factory-Produced Plastics (Fake Wood, Stakes, etc.)
No environmental safety standards exist for materials recycled from high-molecular
organic substances. The Environmental Quality Standards for Soil Pollution can be
considered as one set of standards for inorganic and metal materials, but there are no
standards stipulated for organic materials such as rubber and plastic. It is therefore
necessary to implement tests when this type of recycled material is used under conditions
in which the material comes into direct contact with soil or groundwater, etc.
A wide range of products made from recycled waste plastic is manufactured with a focus
on public works projects. Many of these products compete against wood and concrete
products, and demand for plastic products that make the best use of their characteristics
as substitutes for wood and concrete continues to grow. Recycled products made from
waste plastic that provide features not available with conventional materials are also
being manufactured. However, as the properties of plastic are totally different from those
of conventional material, it is necessary to pay close attention to the fact that the
properties of plastics also differ depending on the type of plastic. The main characteristics
of recycled factory-produced products are shown below.
<Advantages>
-
Durability, chemical-resistance, weather-proofness, wear-resistance, elasticity.
-
Molding complex shapes by integral molding is easily available.
-
Additional strength can be obtained by mixing inorganic filler, or a core material, into
the plastic.
-
Lightweight and therefore easy to use, and can also be dyed or painted.
-
On-site assembly is easy.
<Disadvantages>
-
Thermal-expansion coefficient is higher than that of wood.
-
Bends under heavy loads (except when core material or the like is used)
-
Little resistance against fire.
There are cases in which quality deterioration prevents factory-produced products made
from recycled waste plastic from being recycled for a second or subsequent time. In this
event, these products can usually be used for thermal recycling without any problem.
[Examples of Usage]
307
According to surveys carried out between 1999 and 2002, examples of factory-produced
products made from waste plastic are as follows:
Imitation wood steps (Kanagawa Prefecture)
Imitation wood fences (Toyama Prefecture)
Water absorption/drainage prevention material, embankment-fill drainage material
(Fukui Prefecture)
Benches, imitation wood and imitation wood steps in parks (Yamaguchi Prefecture)
Imitation wood fences in a parking area (Miyazaki Prefecture)
Imitation wood fences (Okinawa Prefecture)
Imitation wood fences (Hokkaido Regional Development Bureau)
Root compaction bags (Kanto Regional Development Bureau)
Protective boards for electric cable guttering (Chubu Regional Development Bureau)
Root compaction bags (Hokkaido Regional Development Bureau)
Root compaction bags, weed-proof sheets (Shikoku Regional Development Bureau)
Root-compaction pouches, water-drainage pipes for retaining walls (Kyushu Regional
Development Bureau)
Imitation wood steps in parks (Sendai)
Imitation wood fences in parks, imitation wood safety barriers for a pond (Sendai)
Imitation wood in a city-administered cemetery (Osaka)
Barrier blocks containing resin foam
L-shaped retaining walls containing resin foam (Kita-Kyushu)
A large number of examples involving recycled plastic imitation wood, recycled plastic
stakes, boards, benches, blocks, etc., are reported in Reference 2).
1) Plastic Recycling Technology (CMC Books): CMC, July 2000
2) Construction Research Institute: Handbook on Recycled Materials Used in
308
5. Recycled Materials Not Mentioned
Uses for recycled materials that have not been mentioned in this manual but are listed
in surveys undertaken in various prefectures and cities by the Ministry of Land,
Infrastructure, and Transport are shown below.
Recycled Material
Usage
Molten Incineration
Vegetation bases, pipe-heating material, rock-wool products
Ash Slag
Molten Sewage
Sludge Incineration
Asphalt admixture (3 cases,) cement raw material (3 cases,)
backfill (4 cases)
Ash
Treated Sewage
Water used in streams, air-conditioners and machinery
Water (Recycled
Water)
Waterworks Sludge
Vegetation on slopes (2 cases)
Coal Ash
Vegetation on slopes, water-retention material (4 cases),
reinforced earth walls (shock absorption layer,) foundation
material
Coal Ash, Glass
Vegetation base material, cleaning base material (2 cases)
Cullet
Recycled Wool
Weed-proof sheets
(Collected Apparel)
Waste Tires
Buffering on the interfiling protection banks of a
landslide-prevention dam, slope-protection material
Waste Paper
Material to improve soil excavations with high water content
Cupola Slag, Foundry
Secondary concrete products (2 cases,) embankment fill
Sand
Desulfurized Gypsum
Soil improvement material (2 cases)
Calcinated Chrome
Subgrade material (2 cases)
Slag
309
Appendix
310
1. Environmental Quality Standards for Soil Pollution
23 August 1991
Environment Agency Ordinance No. 46
Revisions: 1993 Environment Agency Ordinance No. 19; 1994 Environment Agency
Ordinance No. 5; 1994 Environment Agency Ordinance No. 25; 1995 Environment Agency
Ordinance No. 19; 1998 Environment Agency Ordinance No. 21; 2001 Environment
Agency Ordinance No. 16.
The Environmental Quality Standards for Soil Pollution, based on the stipulations laid
down in Article 9 of the Environmental Pollution Prevention Basic Law (Law No. 132 of
1967) regulate the following.
With regard to environmental conditions concerning soil pollution, based on paragraph 1,
Article 16, the Basic Environment law (Law No. 91 of 1993), the standards (hereinafter
referred to as the Environmental Standards) that are deemed desirable to protect the
health of humans and maintain an active and healthy environment and the period by
which these standards are to be achieved shall follow the conditions below.
No. 1 Environmental Standards
Environmental standards are provided for each of the items listed in the [Item]
column of the Additional Chart below, together with the necessary
[Environmental Conditions].
The environmental standards in the above 1 are values measured at locations
regarded as suitable for correctly determining soil pollution conditions in regard
to each of the items in the additional chart, using the measurement methods
listed in the same chart.
The environmental standards in the above 1 are not applicable to soils in
locations where pollution is caused mainly by natural factors, sites where raw
materials are accumulated, landfill sites for waste materials, and facilities
where substances listed as items in the Additional Chart are stored for the
purpose of using or disposing of them.
No. 2 Period for Achieving Environmental Standards, etc.
311
For soil that does not match the environmental standards, efforts must be made
to achieve and maintain the standards as soon as possible in accordance with
the degree and expansion of the pollution, its effect, and the like.
All necessary measures must be taken to prevent the effects of soil pollution on
the environment when the environmental standards are not expected to be
achieved in the short-term.
Additional Chart
Item
Environmental Conditions Measurement Method
The method of measuring values
related to sample solution density is to
conform to the method stipulated in 55
0.01 mg/l or less in sample
Cadmium
solution and less than 1
mg/kg in rice in the case of
agricultural land
of Japan Industrial Standard K0102
(hereinafter referred to as the
Standard), and the method of
measuring values related to
agricultural land is to conform to the
method in Ministry of Agriculture and
Forestry Ordinance No. 47 (June
1971).
Total cyanide
Must not be detected in
sample solution
To conform to the methods stipulated
in Standard 38 (excluding the method
stipulated in Standard 38.1.1).
in Chart 1 of Announcement No. 64
(September 1974) by the
Environmental Agency or the methods
Organic phosphorus
sample solution
stipulated in Standard 31.1, with the
exception of the gas chromatographic
method. (The method for methyl
demeton is to conform to the methods
stipulated in Chart 2 of Announcement
No. 64 (September 1974) by the
Environmental Agency).
Lead
0.01 mg/l or less in sample To conform to the methods stipulated
312
solution
in Standard 54.
Chromium (VI)
solution
in Standard 65.2.
The method of measuring values
related to sample solution density is to
0.01 mg/l or less in sample conform to the method stipulated in
Arsenic
solution, and less than 15
Standard 61, and the method of
mg/kg in soil on
measuring values related to
agricultural land (paddy
agricultural land is to conform to
fields only)
Ministerial Ordinance No. 31 (April
1975) by the General Administrative
Agency of the Cabinet.
Total mercury
0.0005 mg/l or less in
sample solution
(December 1971) by the
Environmental Agency.
Alkyl mercury
sample solution
Environmental Agency and Chart 3 of
Announcement No. 64 (September
1974) by the Environmental Agency.
PCBs
sample solution
To conform to methods stipulated in
Less than 125 mg/kg in soil Ministerial Ordinance No. 66 (October
Copper
on agricultural land (paddy 1972) by the General Administrative
fields only)
Agency of the Cabinet Prime
Minister’s Office.
Dichloromethane
solution
in 5.1, 5.2 or 5.3.2 of Japan Industrial
Standard K0125.
313
1,2-dichloroethane
Trichloroethylene
Tetrachloroethylene
1,3-dichloropropene
sample solution
in 5.1, 5.2, 5.3.1, 5.4.1, or 5.5 of Japan
Industrial Standard K0125.
sample solution
in 5.1, 5.2, 5.3.1, or 5.3.2 of Japan
solution
in 5.1, 5.2, or 5.3.2 of Japan Industrial
Standard K0125.
solution
Standard K0125.
1 mg/l or less in sample
solution
in 5.1, 5.2, 5.3.1, 5.4.1, or 5.5 of Japan
sample solution
in 5.1, 5.2, 5.3.1, 5.4.1, or 5.5 of Japan
solution
in 5.1, 5.2, 5.3.1, 5.4.1, or 5.5 of Japan
solution
in 5.1, 5.2, 5.3.1, 5.4.1, or 5.5 of Japan
sample solution
Standard K0125.
Thiuram
sample solution
Simazine
sample solution
in Item 1 or Item 2 of Chart 5 of
Announcement No. 59 (December
314
Thiobencarb
0.02 mg/l or less in sample in Item 1 or Item 2 of Chart 5 of
solution
Benzene
Selenium
solution
Standard K0125.
solution
in Standard 67.2 or 67.3.
Fluorine
solution
in Standard 34.1 or Chart 6 of
Environmental Agency Report No. 59,
enacted in December 1971.
Boron
1 mg/l or less in sample
in Standard 47.1 or 47.3 and Chart 7 of
solution
Notes
1 Test solution samples are to be created in accordance with the methods stipulated in the
Additional Chart, and these samples are to be used to measure the densities of the
substances.
2 With regard to the densities of cadmium, lead, chromium (VI), arsenic, total mercury,
selenium, fluorine, and boron in the sample solutions, when polluted soil is separated
from the surface of groundwater and the density detected in samples taken from the
actual groundwater does not exceed 0.01 mg, 0.01 mg, 0.05 mg, 0.01 mg, 0.0005 mg,
0.01 mg, 0.8 mg, or 1 mg, respectively, per liter of water, the values for each solution
sample are to be set at 0.03 mg, 0.03 mg, 0.15 mg, 0.03 mg, 0.0015 mg, 0.03 mg, 2.4 mg
and 3 mg, respectively, for each liter of water.
3 [Must not be detected in sample solution] indicates that the results of measurements
implemented in accordance with the methods stipulated in the [Measurement Method]
column are below the relevant content limits.
4 Organic phosphorus includes parathion, methyl parathion, methyl demeton, and EPN.
315
Chart
Sample solutions are to be made in accordance with the following methods:
１. Cadmium, total cyanide, lead, chromium hexavalent, arsenic, total mercury, alkyl
mercury, PCBs, and selenium are to conform to the following methods.
(1) Handling Soil Samples
All collected soil samples are to be stored in glass or other containers to which the
relevant samples do not adhere. Tests are to be carried out immediately after soil
samples are collected. If the tests cannot be carried out immediately, the samples
are to be stored in a dark place and the tests are to be implemented as soon as
possible.
(2) Sample Preparation
All collected soil samples are to be air-dried, to have all small and medium-sized
coarse fragments and wood shards removed, and to have all soil lumps and
particle clumps crushed. The soil that is obtained after the sample has been
passed through a non-metallic sieve with a mesh size of 2 mm is to be thoroughly
mixed.
(3) Sample Solution Preparation
The test sample (units: g) and solvent medium (hydrochloric acid added to distilled
water so that the hydrogen ion density index is between 5.8 and 6.3) (units: ml)
are to be mixed to a mass unit ratio of 10%, and the mixed solution is to be of 500
ml or more.
(4) Elution
The test sample solution is shaken for six consecutive hours in a shaking
apparatus (to be preset to shake 200 times per minute, with a shaking width
between 4 and 5 cm) at normal room temperature (approximately 20 degrees
Celsius) and at normal atmospheric pressure (approximately one atmosphere.)
(5) Test Solution Creation
The test sample solution obtained by implementing procedures (1) to (4) is to be
left for ten to thirty minutes and then separated by centrifugal force for twenty
minutes at a revolution rate of approximately 3,000 rpm. The liquid that collects
at the top of the solution is to be passed through a membrane filter with a pore
size of 0.45 µm. The filtered liquid obtained from this is then accurately measured
so that the required amount is acquired for sample testing.
２. Dichloromethane, carbon tetrachloride, 1,2-dichloroethane, 1,1-dichloroethylene,
316
cis-1,2-dichloroethylene, 1,1,1-trichloroethane, 1,1,2-trichloroethane,
trichloroethylene, tetrachloroethylene, 1,3-dichloropropene, and benzene are to
conform to the following methods.
The properties of these substances are highly volatile, so all collected soil samples
are to be stored in glass or other containers that can be hermetically sealed with
no air space to which the properties of the relevant sample do not adhere. Tests
are to be carried out immediately after soil samples are collected. If the tests
cannot be carried out immediately, the samples are to be stored in a cool, dark
place at a temperature of 4 degrees Celsius or less and the tests are to be
implemented as soon as possible. However, soil samples that contain
1,3-dichloropropene must be frozen for storage purposes.
All small and medium-sized fragments that exceed a particle diameter of
approximately 5 mm, and wood shards, etc., are to be removed from the soil
sample.
are to be mixed to a mass unit ratio of 10% (Note 1) (Note 2) in a screw-top
Erlenmeyer flask into which a stirring bar has been placed, and the top is to be
sealed immediately. The mixed solution at this point must be 500 ml or more, and
the headspace between the surface of the solution and the screw top of the flask is
to be kept to a minimum.
(4) Elution
The test sample solution is to be stirred for four consecutive hours by a magnetic
stirrer at normal room temperature (approximately 20 degrees Celsius) and at
normal atmospheric pressure (approximately one atmosphere) (Note 3).
left for ten to thirty minutes and then suctioned up gently into a glass syringe. A
filter paper holder (made of stainless steel or a material with the same or superior
qualities that matches the diameter of the membrane filter being used) to which a
membrane filter with a pore size of 0.45 µm has been attached is connected to the
syringe and the inside of the syringe is pushed out until all the air and the first
317
few milliliters of liquid have been expelled. The filtered liquid is then separated
into test tubes fitted with plugs, and the liquid is then accurately measured so
that the required amount is acquired for sample testing (Note 4).
Note 1 A stirring bar is placed into the screw-top Erlenmeyer flask that is to be used
and the mass is measured. This is then topped up with water and the mass is
measured again. The difference in the measurements provides the amount of
air space in the screw-top Erlenmeyer flask (units: ml). Once the amount of air
space has been measured, this same value can be used for the second and
subsequent measurements without having to measure it again, as long as the
same container and stirring bar are used.
Note 2 In measuring the cubic content (ml) of each test sample, the amount of water to
be added may be adjusted in order not to leave a head space, which can be
acquired by performing calculation of air space in Note 1.
Note 3 Adjust the magnetic stirrer so that the stirring bar mixes the test sample and
the water equally. Also, make sure that the test sample solution does not
generate heat.
Note 4 Make sure that there is no loss in the amount of the sample to be measured
from the beginning of the measurement to the separation of the filtered
solution.
3. Organic phosphorus, thiuram, simazine, and thiobencarb are to conform to the
following methods.
All collected soil samples are to be stored in glass or other containers to which the
relevant samples do not adhere. Tests are to be carried out immediately after soil
sample collection. If the tests cannot be carried out immediately, the samples are
to be frozen and stored and the tests implemented as soon as possible.
particle clumps crushed. The soil obtained after the sample has been passed
through a non-metallic sieve with a mesh size of 2 mm is to be thoroughly mixed.
are mixed to a mass unit ratio of 10%, and the mixed solution is to be of 1,000 ml
318
or more.
(4) Elution
The test sample solution is to be shaken for six consecutive hours in a shaking
apparatus (to be preset to shake 200 times per minute, with a shaking width
Celsius) and at normal atmospheric pressure (approximately one atmosphere.)
left for ten to thirty minutes and separated by centrifugal force for twenty minutes
at a revolution rate of approximately 3,000 rpm. The liquid that collects at the top
of the solution is to be passed through a membrane filter with a pore size of 0.45
µm. The filtered liquid obtained from this is then accurately measured so that the
required amount is acquired for sample testing.
4. Fluorine and boron are to conform to the following methods.
All collected soil samples are to be stored in polyethylene or other containers to
which the relevant samples do not adhere or elute. Tests are to be carried out
immediately after soil sample collection. If the tests cannot be carried out
immediately, the samples are to be stored in a dark place and the tests
implemented as soon as possible.
particle clumps crushed. The soil that is obtained after the sample has been
passed through a non-metallic sieve with a mesh size of 2 mm is to be thoroughly
mixed.
water so that the hydrogen ion density index is between 5.8 and 6.3) (units of ml)
are to be mixed to a mass unit ratio of 10%, and the mixed solution is to be of 500
ml or more.
(4) Elution
The test sample solution is to be shaken for six consecutive hours in a shaking
apparatus (to be preset to shake 200 times per minute with a shaking width
319
Celsius) and at normal atmospheric pressure (approximately one atmosphere).
The shaking container is to be of polyethylene or a similar material to which the
relevant samples do not adhere or elute.
left for ten to thirty minutes and then separated by centrifugal force for twenty
minutes at a revolution rate of approximately 3,000 rpm. The liquid that collects
at the top of the solution is to be passed through a membrane filter with a pore
size of 0.45 µm. The filtered liquid obtained from this is then to be accurately
measured so that the required amount is acquired for sample testing.
320
2. Enforcement Regulations of the Soil Contamination Countermeasures
Law (Excerpt)
(26 December 2002, Ministerial Ordinance No. 29, Ministry of Environment)
(Abridged)
(Standards Concerning Specific Regions)
Article 18: Of the standards stipulated in paragraph 1, Article 5 of the Ministry of
Environment ordinance, the results of measurements carried out on the amount of
specified toxic substances eluted from soil to which water has been added in accordance
with the methods stipulated by the Minister for the Environment in Law 5, Article 3
Section 4 are to conform to the requirements shown in the chart below in accordance
with the type categories for specified toxic substances listed in Additional Chart 2.
2. Of the standards stipulated in paragraph 1, Article 5 of the Ministry of Environment
ordinance, the results of measurements carried out on the amount of specified toxic
substances contained in soil in accordance with the methods stipulated by the
Environment Minister in clause 2, paragraph 4, Article 5 are to conform to the
requirements shown in chart 3 below in accordance with the type categories for
specified toxic substances listed in Additional Chart 3.
Chart 2 (Related to paragraph 1, Article 18)
Specified Toxic
Requirement
Substance Type
Cadmium and its
0.01 mg/l or less of cadmium
compounds
Chromium hexavalent
0.05 mg/l or less of chromium hexavalent
compounds
Simazine
0.003 mg/l or less of simazine
Cyanide compounds
Thiobencarb
0.02
0.002 mg/l or less of carbon tetrachloride
1,2-dichloroethane
0.004 mg/l or less of 1,2-dichloroethane
0.02 mg/l or less of 1,1-dichloroethylene
mg/l or less of thiobencarb
321
Cis-1,2-dichloroethylene 0.04 mg/l or less of cis-1,2-dichloroethylene
1,3-dichloropropane
0.0０2 mg/l or less of 1,3-dichloropropane
Dichloromethane
0.02 mg/l or less of dichloromethane
Mercury and its
0.0005 mg/l or less of mercury, and alkyl mercury must not be
compounds
detected
Selenium and its
0.01 mg/l or less of selenium
compounds
Tetrachloroethylene
0.01 mg/l or less of tetrachloroethylene
Thiuram
0.006 mg/l or less of thiuram
1 mg/l or less of 1,1,1-trichloroethane
0.006 mg/l or less of 1,1,2-trichloroethane
Trichloroethylene
0.03 mg/l or less of trichloroethylene
Lead and its compounds 0.01 mg/l or less of lead and its compounds
Arsenic and its
0.01 mg/l or less of arsenic
compounds
Fluorine and its
0.8 mg/l or less of fluorine
compounds
Benzene
0.01 mg/l or less of benzene
Boron and its
1 mg/l or less of boron
compounds
Polychlorinated
biphenyls
Organic phosphorous
and its compounds
322
Chart 3 (Related to paragraph 2, Article 18)
Specified Toxic
Requirement
Substance Type
Cadmium and its
150 mg/kg or less of cadmium in soil sample
compounds
Chromium
250 mg/kg or less of chromium(VI) in soil sample
hexavalent
compounds
Cyanide compounds 50 mg/kg or less of free cyanide in soil samples
Mercury and its
15 mg/kg or less of mercury in soil sample
compounds
Selenium and its
150 mg/kg or less of selenium in soil sample
compounds
Lead and its
150 mg/kg or less of lead in soil sample
compounds
Arsenic and its
150 mg/kg or less of arsenic in soil sample
compounds
Fluorine and its
4000 mg/kg or less of fluorine in soil sample
compounds
Boron and its
4000 mg/kg or less of boron in soil sample
compounds
323
3. Concerning Determination of Measurement Method with Regard to Toxic
Substances Contained in Soil
The measurement methods to be used in surveys on the toxic content in soil, as
stipulated by the Minister for the Environment in accordance with clause 2, paragraph
4, Article 5 of the Enforcement Regulations on Soil Contamination Countermeasures
Law (Ministry for the Environment Ordinance No. 19, 2002), are as follows.
The measurement methods to be used in surveys on the toxic content in soil, as
stipulated by the Minister of Environment in accordance with clause 2, paragraph 4,
Article 5 of the Enforcement Regulations on Soil Contamination Countermeasures Law,
are as follows.
1. Measurements are to be implemented for the specified toxic substances listed in the
Specified Toxic Substance Types column of the Additional Chart by creating test
solution samples in accordance with the methods explained in the Chart and carrying
out the measurements in accordance with the methods listed in the Measurement
Methods column of the Additional Chart.
2. The masses of the test samples created in accordance with the instructions provided
in Chart 2 and samples made by the same procedures and subsequently dried for
approximately four hours at a temperature of 105 degrees Celsius are compared to
obtain the water content of the test sample. Then the amount of target substances
acquired in the above 1 is converted into the mass contained in 1 kg of dried soil.
Additional Chart
Specified Toxic
Measurement Method
Substance Type
Cadmium and its
To conform to the methods stipulated in 55 of Japan
compounds
Industrial Standard K0102 (hereinafter referred to as the
Standard).
Chromium hexavalent
To conform to the methods stipulated in Standard 65.2.
compounds
Cyanide compounds
To conform to the methods stipulated in Standard 38
(excluding the method stipulated in Standard 38.1).
Mercury and its
To conform to the methods stipulated in Chart 1 of the
compounds
Environmental Agency Report No. 59, enacted in December
1971 (Environmental Standards for Water Pollution)
(hereinafter known as the Environmental Standards for
Water Quality.)
Selenium and its
To conform to the methods stipulated in Standard 67.2 and
compounds
67.3.
To conform to the methods stipulated in Standard 54.
324
Arsenic and its
To conform to the methods stipulated in Standard 61.
compounds
Fluorine and its
To conform to the methods stipulated in Standard 34.1 or
compounds
Standard 34.1c) (excluding Article 3 of Provision 6) and the
methods stipulated in Chart 6 of the Announcement on
Environmental Standards for Water Quality Report.
Boron and its
To conform to the methods stipulated in Standard 47.1 or
compounds
Standard 47.3 and the methods stipulated in Chart 7 of the
Environmental Standards for Water Quality Report.
Addendum
Sample solutions are to be made in accordance with the following methods.
1. Handling Soil Samples
All collected soil samples are to be stored in polyethylene or other containers to which
the relevant samples do not adhere or elute. Tests are to be carried out immediately
after soil sample collection. If the tests cannot be carried out immediately, the samples
are to be stored in a dark place and the tests are to be implemented as soon as
possible.
2. Sample Preparation
course fragments and wood shards removed, and to have all soil lumps and particle
clumps pulverized. The soil that is obtained after the sample has been passed through
a non-metallic sieve with a mesh size of 2 mm is to be thoroughly mixed.
3. Test Solution Creation
(1) The method is to be as follows for cadmium and its compounds, mercury and its
compounds, selenium and its compounds, lead and its compounds, arsenic and its
compounds, fluorine and its compounds, and boron and its compounds.
a. Sample Solution Preparation
A test sample of 6 g or more is prepared, and this sample (units: g) and the solvent
medium (hydrochloric acid added to distilled water so that the hydrochloric acid
concentration is 1 mol/l) (units: ml) are to be mixed to a mass unit ratio of 3%.
b. Elution
The test sample solution made is to be shaken for two consecutive hours in a shaking
apparatus (to be preset to shake 200 times per minute with a shaking width between
4 and 5 cm) at normal room temperature (approximately 25 degrees Celsius) and
normal atmospheric pressure (approximately one atmosphere.) The container for
325
shaking is to be of polyethylene or a similar material to which the relevant sample
does not adhere or elute, and it must have a capacity of 1.5 times more than the
solution being tested.
c. Test Solution Creation
The test sample solution obtained through shaking in procedure in b is to be left for
ten to thirty minutes and then separated by centrifugal force if necessary. The liquid
that collects at the top of the solution is to be passed through a membrane filter with a
pore size of 0.45 µm. The filtered liquid obtained from this is then to be accurately
(2) The method is to be as follows for chromium hexavalent compounds.
a. Sample Solution Preparation
A test sample of 6 g or more is to be prepared, and this sample (units: g) and the
solvent medium (0.005 mol of sodium carbonate or 0.53 g of anhydrous sodium
carbonate) and 0.01 mol of sodium hydrogen carbonate (0.84 g of sodium hydrogen
carbonate) dissolved in distilled water to make 1 liter) (units: ml) are to be mixed to a
mass unit ratio of 3%.
b. Elution
The test sample solution is to be shaken for two consecutive hours in a shaking
apparatus (to be preset to shake 200 times per minute with a shaking width between
4 and 5 cm) at normal room temperature (approximately 25 degrees Celsius) and
normal atmospheric pressure (approximately one atmosphere.) The container for
shaking is to be of polyethylene or a similar material to which the relevant samples do
not adhere or elute, and it must have a capacity of 1.5 times more than the solution
being tested.
c. Test Solution Creation
The test sample solution obtained through shaking in procedure in b is to be left for
ten to thirty minutes and then separated by centrifugal force if necessary. The liquid
that collects at the top of the solution is to be passed through a membrane filter with a
pore size of 0.45 µm. The filtered liquid obtained from this is then to be accurately
(3) The method is to be as follows for cyanide compounds.
a. Measure between 5 g and 10 g of the test sample into a distillation flask, and then
add 250 ml of water.
b. Add a few drops of phenolphthalein solution (5 g/l: dissolve 0.5 g of phenolphthalein
in 50 ml of ethanol (95%) and add water to make 100 ml) to the test sample as an
indicator. If the result is alkaline, add sulfuric acid (1 + 35) until the redness of the
326
solution disappears.
c. Add 20 ml of a zinc acetate solution (100 g/l: dissolve 100 g of zinc acetate
(dihydrogen chloride) in water to make 1 liter).
d. Connect the distillation flask to the distiller. Using a 250-ml stoppered measuring
cylinder as the receiver, pour 30 ml of sodium hydroxide solution into it and dip the tip
of the cooling tube in the sodium hydroxide solution. An illustration of the distiller is
shown below.
e. Add 10 ml of sulfuric acid (1+35) to the distillation flask.
f. Leave the distillation flask for a few minutes, and then apply heat to cause
evaporation at a rate of 2 to 3 ml per minute (Note 1). When the liquid volume in the
receiver reaches approximately 180 ml, separate the tip of the cooling tube from the
liquid and halt the evaporation. Cleanse the inside and outside of the cooling tube
with a small quantity of water, and then mix the water used for cleansing with the
evaporation liquid.
g. Add a few drops of the phenolphthalein solution (5 g/l) and then neutralize this in
acetic acid (1+9) as swiftly as possible to prevent the cyanide ion from sublimating
into hydrocyanic acid while the stopper is removed. Add water to make 250 ml, and
then use this as the test solution (Note 2).
Note 1: The hydrocyanic acid will not be distilled completely if the distillation speed is
too fast, so make sure that the speed is not more than 3 ml per minute. Also, make
sure that the tip of the cooling tube is constantly 15 mm below the surface of the liquid
during the distillation procedure.
Note 2: Negative differentials will occur in absorption photometry, for example by the
pyridine/pyrazolone method, if the distilled liquid contains sulfide ion. So when
performing tests on solutions with high sulfide content, add 10 ml of zinc acetate
ammonia solution (add 12 g of zinc acetate dehydrate to 35 ml of concentrated
ammonia water, and then add water to make 100 ml) to precipitate.
327
328
The environmental risk evaluation standards in this manual use effluent values
stipulated in “Environmental Quality Standards for Soil Pollution” (Ministerial
Ordinance No. 46, 1991, Ministry of Environment) (excluding effluent amount of copper
applied to only rice patch) and paragraph 1, Article 18 and Addendum 2 of
“Enforcement Regulations of Soil Contamination Countermeasures Law” (Ministerial
Ordinance No. 29, 2002, Ministry of Environment). Toxic content values are stipulated
in paragraph 2 and Addendum 3 of “Enforcement Regulations of Soil Contamination
Countermeasures Law”.
The above is summarized as follows:
(Items marked with the “○” symbol are applicable only to materials solubilized at high
temperatures or processed in similar ways – e.g. molten slag.)
329
Item
(Effluent Standard)
(Toxic Content
Standard)
○ Cadmium and its compounds
0.01 mg/L or less
150 mg/kg or less
○ Chromium hexavalent
0.05 mg/L or less
250 mg/kg or less
compounds
Simazine
0.003 mg/L or less
Cyanide
50 mg/kg or less (free
cyanide)
Thiobencarb
0.02 mg/L or less
0.002 mg/L or less
1,2-dichloroethane
0.004 mg/L or less
0.02 mg/L or less
0.04 mg/L or less
1,3-dichloropropene
0.002 mg/L or less
Dichloromethane
0.02 mg/L or less
○ Mercury and its compounds
0.0005 mg/L or less
15 mg/kg or less
○ Selenium and its compounds
0.01 mg/L or less
150 mg/kg or less
Tetrachloroethylene
0.01 mg/L or less
Thiuram
0.006 mg/L or less
1 mg/L or less
0.006 mg/L or less
Trichloroethylene
0.03 mg/L or less
○ Lead and its compounds
0.01 mg/L or less
150 mg/kg or less
○ Arsenic and its compounds
0.01 mg/L or less
150 mg/kg or less
Fluorine and its compounds
0.8 mg/L or less
4,000 mg/kg or less
Benzene
0.01 mg/L or less
Boron and its compounds
1 mg/L or less
Polychlorinated biphenyls
(PCBs)
Organic phosphorus
compounds
Alkyl mercury
330
4,000 mg/kg or less

Technical Manual for the Use of Recycled Materials Generated by

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