Curb, barrier, sidewalk and multipurpose apllications

Transcription

Concrete Slipform Paving Manual
Part 1: Curb, barrier, sidewalk
and multipurpose applications
Concrete Slipform Paving Manual
Part 1: Curb, barrier, sidewalk
and multipurpose applications
Content
1 Basic design of multipurpose slipform pavers 9
1.1
Paver components
12
1.2
Operator’s platform
14
1.3
Paver setup options
16
2 Machines and application examples
23
2.1
Machine models and performance ranges
26
2.1.1
Slipform paver SP 150
26
2.1.2
27
2.1.3
28
2.2
Application examples
29
2.2.1 Pouring curbs
29
2.2.2 Pouring curb and gutter profiles
30
2.2.3
Pouring median barriers
31
2.2.4
Pouring canals
32
2.2.5 Paving slabs
33
3 Site logistics
35
3.1
Basic principles
38
3.2
Installing stringline
42
4 Preparation of the base
47
4.1
The base of concrete profiles
50
4.2
Preparing the base with a trimmer
52
5 Concrete feeding
55
5.1
Belt conveyor 58
5.2
Auger conveyor 60
5.3
Cross-feeding
62
5.4
Dumping the concrete mix in front of the paver
64
5.5
Chute and hopper
65
5.6
Push bar
66
6 Concrete slipforming / Molds 69
6.1
Mold function and design
72
6.2
Mold options
74
6.3
Additional functions
78
6.3.1
Combination mold
78
6.3.2
Curb depressor
80
6.3.3
Sideplates
81
6.3.4
Mold mounts
82
6.3.5
Adjustable mold mount
84
6.3.6
Quick-change mold mounting system
86
6.4 Basic classification of different mold types
88
6.5 Special molds
90
7 Concrete compaction
97
7.1
Vibrator functionality
100
7.2 Vibrator designs
102
7.2.1 Straight vibrators
102
7.2.2 Curved vibrators 102
7.3 Types of vibrator operation
103
7.3.1 Electric vibrators
103
7.3.2 Hydraulic vibrators
103
7.4 Theoretical effective vibrator radius
104
7.5 Positioning the vibrators
106
7.5.1 Offset applications
106
7.5.2 Slab paving
108
7.6 Determining the frequency
110
8 Curing
113
8.1
Weather protection
116
8.1.1
Treatment with curing compounds
116
8.1.2 Curing blankets
118
8.1.3 Continuous moistening with water
119
Content
8.2 Cutting joints
120
8.2.1
Contraction joints
120
8.2.2
Expansion joints
122
8.3
Sealing joints
123
8.4
Concrete testing methods
124
8.4.1 Testing fresh concrete
124
8.4.1.1 Tests to determine concrete consistency
125
8.4.1.2 Determining the air content by means of the pressure gauge method
134
8.4.2 Testing hardened concrete
136
9 Concrete reinforcement
141
9.1 Basics of concrete reinforcement
144
9.2
Types of concrete reinforcement
146
10 Machine operation
151
10.1 Requirement of a control system
154
10.2
Machine operation by means of stringline
156
10.2.1 Level control
156
10.2.2
Steering control
157
10.2.3 Machine behavior in relation to steering sensor position when driving straight ahead 158
10.2.4
Machine behavior without additional steering sensor when driving through outside radii
160
10.2.5
Machine behavior with additional steering sensor when driving through outside radii
162
10.2.6
Machine behavior when driving through inside radii
164
10.3 Machine operation by means of a 3D system
166
10.3.1
Appraisal of the 3D control system
166
10.3.2
Digital terrain model using GPS / GNSS
166
10.3.3
Optical measuring systems
168
10.3.4
Functionality
170
10.3.5
Benefits
171
11 Parameters influencing the paving process
173
11.1
Concrete mix
176
11.2
Paving parameters
178
11.3
Machine settings
179
11.4 Interaction of machine weight and concrete buoyancy
180
12 Paving errors and error correction
12.1
Illustrated examples and recommended corrective action
13 Basics of design
183
186
195
13.1
Concrete requirements
198
13.1.1
Concrete requirements for offset paving 198
13.1.2
Concrete requirements for slab paving 199
13.2 Paving capacity
200
13.2.1
Paving capacity in offset paving
200
13.2.2
Paving capacity in slab paving
201
13.3 Conveying capacity of feeding equipment
202
13.3.1
Conveying capacity of auger conveyor
202
13.3.2
Conveying capacity of belt conveyor
204
14 Concrete science
207
14.1
Composition of the concrete mix
210
14.2
Aggregate and grading curve
212
14.3
Concrete properties
217
14.4
Distinguishing characteristics
218
14.5
Production in the concrete plant
219
14.6
Causes of poor concrete quality
220
15 Bibliography and image credits
223
Wirtgen slipform pavers –
A decade’s long global presence
6 // 7
1 Basic design of multipurpose
slipform pavers 1.1
Paver components
12
1.2
Operator’s platform
14
1.3
Paver setup options
16
8 // 9
Multipurpose slipform pavers have proven to be
the machines of choice for the production of
canals, median barriers and curbs.
Slipform pavers work in a continuous operation
and do not require static formwork or shuttering.
For offset paving applications, molds are mounted
to one side of the paver; for inset paving, they are
mounted between the paver’s tracks.
Wirtgen slipform pavers are designed to be compact and to minimize jobsite space requirements.
A broad variety of different mold options enables
a broad range of applications.
The pavers are distinctive for their high flexibility.
They are capable of producing everything from
small curbs as well as barriers, slabs and other
larger cross sections.
10 // 11
1.1
Paver components
Pivoting leg for adjustment of tracks to site
conditions
Transverse auger for feeding
molds mounted far to one side
of the machine frame
Walk-through operator’s
platform offers a good view
of both the machine and the
construction site
Water tank
Hydraulically driven, separately
height-adjustable and steerable
track units
Telescoping main frame
Adjustable mold mount can
be placed on either left or
right side of the machine
Heavy-duty main frame
Power unit with
diesel engine
Concrete conveyor
(can be auger as shown or belt)
Adjustable mold mount can be
placed on either left or right side
of the machine
Machine post with lift cylinder
shown telescoped to one side
12 // 13
1.2 Operator’s platform
The paver is operated from an ergonomically
designed operator’s platform. Depending on the
application, the operator’s console can be located
on the left or right side of the machine to provide
Exceptional visibility all round from the operator’s platform
the operator with the optimal view of the controls,
construction site and machine functions. Highly
automated control systems simplify the operator’s
job and facilitate highly productive operation.
Ergonomically designed machine operator platform
14 // 15
1.3 Paver setup options
Slipform pavers are of modular design, and have
a high degree of flexibility. Various possibilities
for arranging the tracks, mounting the molds and
arranging the concrete feeding systems enable
the machines to be tailored to a wide array of
situations.
Slipform pavers are equipped with either three
or four tracks. Machines used for paving smaller
profiles usually require only three tracks. The front
crawlers can be mounted on rigid or pivoting legs.
A pivoting leg enables the crawler to be adjusted
to the left or right. Certain models offer further adjustment options to the left or right when equipped
with an additional adjustable crawler suspension
at the front of the main frame. All of these adjustment options enable the machine’s stability to be
adapted to jobsite conditions. Depending on the
specific application, the front crawler can be positioned within or outside the width of the machine
frame. With certain models, the rear crawlers can
be telescoped for increased stability and when
paving wide concrete slabs.
Molds can be mounted on the left or right side of
the machine. A telescoping mold mount enables
the mold to be vertically and horizontally adjusted.
The telescoping adjustment allows the use of offset molds of different sizes, and enables the paver
to safely negotiate any obstacle.
The belt or auger conveyor can be mounted at
different points on the machine. With its wide
range of motion and adjustability, the conveyor
can feed concrete to the hopper in the majority
of both inset and offset applications.
Expert’s tip:
• Adjust the position of the tracks to con
ditions on the construction site!
• Position the tracks to achieve maximum
machine stability!
Auger conveyor
Front post
Working direction
Mold mounted
on left side
Fully retracted rear post
Safety barrier (offset)
Option 1: Machine on three tracks for offset pouring
16 // 17
1.3
Paver setup options
Transverse auger
Working direction
Mold mounted on right side
Auger conveyor
Pivoting
front post
Option 2: Machine on four tracks for offset pouring
Fully retracted
rear post
Belt conveyor
Pivoting front post
Working direction
Mold mounted
between the tracks
Fully telescoped rear post
Bicycle path /
Agricultural road (inset)
Option 3: Machine on four tracks for inset paving of a concrete slab
18 // 19
1.3
Paver setup options
Pivoting front post
Working direction
Fully retracted
rear post
Mold mounted
on left side
Belt conveyor
and transverse auger
Option 4: Machine on four tracks for offset paving
Belt conveyor
Working direction
Fully retracted
right rear post
Fully telescoped
left rear post
Pivoting front post
Mold mounted
on left side
Bicycle path /
Agricultural road (offset)
Option 5: Machine on four tracks for offset paving of a concrete slab
20 // 21
2
Machines and application examples
2.1
Machine models and performance ranges
26
2.1.1
26
2.1.2
27
2.1.3
28
2.2
Application examples
29
2.2.1 Pouring curbs 29
2.2.2 Pouring curb and gutter profiles
30
2.2.3 Pouring median barriers 31
2.2.4 Pouring canals 32
2.2.5 Paving slabs 33
22 // 23
Offset slipform pavers are distinctive for their
broad range of applications in the production of
different concrete profiles. To meet the specific
requirements placed on them, the various paver
models differ in size, weight, engine power and
equipment features.
The machines are capable of producing profiles
of most diverse geometries, such as drainage
gutters, canals, curbs and narrow paths, or
traffic barriers of up to 2.20 m (7’3”) in height.
The profiles can be produced to comply with
various national standards, or can be customized
to create nearly any given shape.
The modular design of the slipform pavers using
standard interfaces enables easy mounting of the
different concrete molds.
24 // 25
2.1 Machine models and performance ranges
2.1.1
This slipform paver from Wirtgen is suitable for
curb, curb and gutter, barrier, sidewalk and other
offset applications. It can be changed quickly on
site to pour from either side. The machine’s
compact design ensures ease of transport.
Paving width *
up to 1.5 m / 4’11” inset
Max. offset height
1,000 mm / 3’3”
Engine rating
60 kW / 82 PS / 80 HP
Operating weight **
8.8 – 11.1 t / 19,400 – 24,500 lbs
Number of crawlers
3
Travel drive
hydraulic / crawlers
Offset mold
yes
* = Please consult factory for special paving widths and options
** = Weights depend on machine configuration and working width
2.1.2
The SP 250 is also used mainly for offset applications. Molds can be mounted on the left or
right side of the machine. When pouring offset,
the standard three-tracked machine is capable of
placing concrete slabs at widths of up to 1.80 m
(5’11”), while the four-tracked model can pave at
widths of up to 2.50 m (8’2”). The machine’s maximum paving width when paving inset is 2.50 m
(8’2”) – or 3.50 m (11’6”) when used with a special
adapter. Customized modifications permit to pour
a multitude of special applications.
Paving width *
1.00 – 3.50 m / 3’3” – 11’6”
Max. offset height
1,800 mm / 5’11”
Engine rating
74 kW / 101 PS / 99 HP
Operating weight **
12 – 18.5 t / 26,500 - 41,000 lbs
Number of crawlers
3 (optional 4)
Travel drive
Offset mold
yes
26 // 27
2.1 Machine models and performance ranges
2.1.3
The modular design of the SP 500 enables it
not only to pave but to also pour median barrier
(including variable barrier) at heights of up to
2.20 m (7’3”). Customized modifications permit
even more and different paving applications.
Paving width *
2.00 – 6.00 m / 6’7” – 19’8”
Max. offset height
2,200 mm / 7’3”
Engine rating
131 kW / 178 PS / 176 HP
Operating weight **
14 – 42 t / 31,000 - 92,500 lbs
Number of crawlers
3 (optional 4)
Travel drive
Offset mold
yes
2.2 Application examples
2.2.1
Pouring curbs
he mold can be mounted on the left or right
T
side of the machine in accordance with jobsite
requirements.
hanging the mold from the right to the left side
C
of the machine or vice versa is effected quickly
on site.
Expert’s tip:
Slipform pavers are exceptionally fast and efficient
machines for pouring curbs. Molds can be de
signed to meet nearly any requirement.
• Increase the number of line rods or use
PVC pipe when paving in radii to produce a
concrete profile that is as evenly rounded as
possible!
28 // 29
2.2.2
Pouring curb and gutter profiles
Expert’s tip:
• Set the vertical distance between the
stringline and the upper edge of the profile
to a round number – e.g. 200 mm – to allow
simple control and monitoring.
Another concrete profile paved in offset application
is curb and gutter.
The combined curb and water gutter is poured in
a single operation. Molds for pouring curb and
gutter can be designed in nearly any given
shape.
• Caution! Tripping hazard! Familiarize site staff
with the potential adverse effects of touching
the stringlines.
2.2.3
Pouring median barriers
Slipform pavers are the most economical solution
for placing traffic barriers. Traffic barrier profiles of
variable geometry or height are available.
Median barriers can be poured with or without reinforcing steel. When using reinforcing steel, cable
can be fed into ports in the front of the mold, or an
open front mold can pour over preset steel cage.
heir high degree of impact resistance provides
T
concrete safety barriers with high containment
performance levels.
oncrete safety barriers can be produced in
C
many different standardized or special designs.
arriers can be designed as boundaries for both
B
the central reservation and the verge side of
roads.
30 // 31
2.2.4
Pouring canals
Slipform pavers are capable of pouring canals of
most diverse cross-sections and shapes in both
offset (above) and inset application (left).
The range of products includes, for instance, rainwater gutters, cable ducts and large canals.
Expert’s tip:
• Secure molds mounted far to one side of the
machine by means of turnbuckles to prevent
the mold from sagging or moving during the
paving operation!
2.2.5
Paving slabs
Depending on the number and arrangement of the
crawlers, Wirtgen slipform pavers are capable of
paving paths and other types of concrete slabs
in both offset (above) and inset application (left).
Typical applications include the paving of hard
shoulders, bicycle paths or agricultural roads.
Expert’s tip:
• Check the paver’s stability and center of gravity if working with the mold mounted far in
the offset position – install a counterweight,
if required!
32 // 33
3
Site logistics
3.1
Basic principles
38
3.2
Installing stringline 42
34 // 35
Enormous deadline pressure and the interdependence of various project divisions are character
istic of many construction projects today – with
the result that any departure from schedule incurs
tremendous additional costs. Careful planning –
in particular with regard to the logistics of concrete
supply – is therefore an essential prerequisite
for smooth progress.
Yet another factor to be considered is that, on
smaller construction sites, road closures are
usually not possible; instead, the operations are
carried out in moving traffic.
36 // 37
3.1
Basic principles
When fresh concrete is delivered, the mixer pulls out of the moving traffic
Coordinate the paving process with the
other project divisions in order to guarantee
continuous concrete delivery.
Consider the distance between concrete plant
and construction site: the concrete should be
fully processed within 90 minutes.
Consult with the concrete mixing plant(s) as to
whether the supply of concrete will be ensured
as scheduled.
Ensure sufficiently large access routes to the
paver.
Check condition and quality of the concrete
immediately after the first delivery and, if
necessary, have the concrete consistency
corrected within the permissible parameters.
Check if the paver – in particular the crawlers –
can safely travel along the entire section to be
paved.
Having delivered the concrete, the mixer merges into the moving traffic
Organize the number of transport vehicles to
ensure continuous material supply and minimize
waiting periods. Avoid stop-and-go to ensure a
high-quality finished product.
During offset paving, make sure that transport
vehicles can move along with the flowing traffic
for pulling in ahead of the paver.
If possible, detour moving traffic at a safe
distance from the construction site.
Check that the slipform paver is fully functional
prior to commencing the paving operation (filling
levels, electric and hydraulic functions etc.).
38 // 39
3.1 Basic principles
Checking the concrete profile at regular intervals
If using an automatic leveling system, make sure
that the sensors can work smoothly and without
any obstructions.
aintain consistent paving speed as much as
M
possible. If the supply of concrete mix is restrict
ed, it is better to continue the paving operation
at a slow but steady speed rather than stopping.
If the supply of concrete mix is interrupted for
longer periods, it is advisable to fully use the
material available on site and to clean the
machine afterwards.
heck the paving thickness, dimensional stabiliC
ty and surface quality at regular intervals during
the paving operation to prevent paving errors.
Continuous concrete supply
heck the composition of the concrete mix at
C
regular intervals (internal or external control).
hen paving reinforced concrete profiles, pro
W
vide for appropriate daily quantities of the type
of reinforcement to be used.
ake sure that sufficient supplies of blankets,
M
curing compounds or similar are available for
curing of the concrete profiles or slabs.
ake account of weather conditions during the
T
paving phase: if possible, paving should take
place at temperatures between 5°C (40°F) and
30°C (85°F) only.
ervice and thoroughly clean the slipform paver
S
each day after the end of work, and remove any
remaining concrete material.
40 // 41
3.2
Installing stringline
Clamp
Line rod
Stake
Tension winch
Ground spike
Ground spike
Components required for the tensioning of stringlines
rive or insert one stake at least every 7 meters
D
(23’) on straight sections.
n alternative option is the use of stakes with
A
solid bases.
Slide the clamp onto the stake,
or, if using a clamping base,
It is important to make sure that the stakes
stand upright, as this will facilitate precise
adjustment of the stringline.
slide the clamping base onto the stake and
secure by means of the clamping screw.
An alternative option is the use of self-clamping
spring brackets.
In radii, the stakes need to be arranged
at sufficiently narrow intervals to minimize
tangents. PVC pipe and plastic strip can also
be used.
ension the stringline prior to fastening it to
T
the line rods. Tensioning of the stringline after
fastening to the line rods may result in a
misalignment of the stringline.
he stakes should be arranged at a distance of
T
approx. 150 mm to 200 mm (6” to 8”) behind
the actual position of the stringline to enable the
level sensors to safely pass the stakes.
he stringline should be arranged at a distance
T
of approx. 200 mm to 900 mm (8” to 35”) from
the edge of the profile to be paved.
he line rod is fastened to the stake by means of
T
either a clamp or a clamping base; clamps are
generally used for offset paving.
Pass the line rod through the bores of the clamp,
or, if using a clamping base,
pass the line rod through the bore of the clamp
ing base and secure by means of the clamping
screw.
e sure to fasten all of the line rods on the same
B
side of the stakes, as this will facilitate the in
stallation of the stringline.
Fastening of the line rod to a clamping base
42 // 43
3.2 Installing stringline
Stringline installed in a bend
s operating conditions may vary greatly from
A
one project to the next, installation of stringline
needs to be tailored to the requirements of each
specific application. For instance, if sensing is to
be effected along the upper side or lower side of
the stringline.
o enable the sensor arm to run smoothly along
T
the line rods during the paving operation, the
rods are bent slightly downwards when sensing
along the lower side of the stringline, or slightly
upwards when sensing along the upper side of
the stringline.
orrect installation of stringline is of vital im
C
portance, as the slipform paver will later copy
the path of the stringline.
ny mistake made during installation of the
A
stringline will inevitably be reflected in the
completed concrete structure.
he greater the distance from the stringline to
T
the machine, the more the sensing accuracy of
the sensors will decrease. Great distances can
therefore cause variations in the measurement
of the set values and thus lead to inaccurate
paving results.
Checking the height of the stringline in a bend
he stringline is usually installed to the left
T
or right side of the paver; depending on site
conditions, however, it can also be positioned
between the machine’s tracks.
o ensure high paving quality, the tensioned
T
stringline should be carefully checked once
again in a final step by means of, for instance,
a gauge and level.
44 // 45
4
Preparation of the base
4.1
The base of concrete profiles
50
4.2
Preparing the base with a trimmer
52
46 // 47
Success in concrete paving is determined to a
significant extent by the adhesive bond of the
materials used in the process with the base.
Different processes are available for preparation of
the base to ensure that a good bond is achieved.
48 // 49
4.1 The base of concrete profiles
Concrete profiles should always be placed on top
of a stabilized or compacted base. This may be
either stabilized topsoil or a base layer of crushed
stone, possibly with an underlying additional frost
blanket. Depending on the specification and intended use, however, the base may also be
cement-stabilized. Stabilized topsoil or a base
layer of crushed stone is generally suitable as a
base for curb and gutter profiles or narrow slabs,
whilst base layers are the preferred base for safety
barriers.
Base of profile
Curb and gutter
Bicycle path / Narrow slab
Safety barrier
Soft, unstabilized
subsoil
suitable to a limited
extent
extent
extent
Stabilized soil
well suitable depending
on load
on load
unsuitable
Crushed stone
on load
on load
unsuitable
Asphalt
suitable
suitable
suitable
Cement-stabilized or
hydraulically bound
base layer
well suitable
well suitable
well suitable
Paving a concrete profile on a base of crushed stone
Paving a safety barrier on an asphalt base
50 // 51
4.2 Preparing the base with a trimmer
One method of preparing the base involves fine
grade adjustment with a trimmer. This process
ensures uniform paving and maximum concrete
yield. The trimmer is positioned underneath the
machine in front of the mold. It is vertically and
horizontally adjustable and levels the subgrade
Trimmer with spread auger
down to the specified depth. The working width
can be extended in modular design (requires conversion). Depending on the trimmer configuration,
the material can be conveyed either towards the
center or towards the periphery of the machine.
Ground prepared with a trimmer
The trimmer is positioned in front of the mold
52 // 53
5
Concrete feeding
5.1
Belt conveyor 58
5.2
Auger conveyor
60
5.3
Cross-feeding
62
5.4
Dumping the concrete mix in front of the paver
64
5.5
Chute and hopper
65
5.6
Push bar
66
54 // 55
Continuous feeding of homogeneous concrete into
the mold is an essential prerequisite for successful
slipforming.
accepts the material delivered by a concrete mixer
truck and transports it to a hopper located above
the mold.
Offset slipform pavers are therefore equipped
with either auger or belt conveyors. The conveyor
Conveyors can be used for pouring concrete
profiles in both offset and inset applications.
56 // 57
5.1 Belt conveyor
The hydraulically operated belt conveyor is extra
wide to ensure sufficient concrete quantities at
all times. The conveying speed is continuously
adjustable, enabling the quantity of concrete to
match both the size of the profile’s cross-section
and the advance speed of the slipform paver.
Some slipform paver models additionally permit
the conveyor to be mounted at different points
of the machine. This feature allows for single
lane pouring, in which the transit mixer and the
machine both travel in one lane. This is particularly
helpful on jobsites where space is limited.
Depending on customer specification, the belt
conveyor can optionally be adjusted either manually or hydraulically from the operator’s platform,
thus reducing the time required for conversion.
The conveyor can be slewed, moved in longitudinal direction and height, and adjusted in slope.
Certain machine models additionally permit the
conveyor to be adjusted laterally, which allows
more flexibility for various pouring configurations.
Flexibility on the construction site is increased
further by the use of short or long belt conveyors.
In folding design, the conveyor can be folded
hydraulically - a feature which permits transport of
the slipform paver on shorter vehicles.
Belt conveyors are distinctive for their ease of
maintenance. They are easy to clean and subject
to little wear and tear.
Transporting concrete into the offset mold via a belt conveyor
Standard conveyor and folding conveyor
Folding conveyor in transport position
Expert’s tip:
• Spray all conveyor parts which come into
contact with concrete with a release agent
prior to commencing work! This will facilitate
cleaning of the machine.
• Lubricate all moving parts at regular inter
vals! This will extend the conveyor’s lifespan.
• Clean belt conveyor scrapers at regular
intervals!
Trough at the belt conveyor to accept concrete from the
concrete mixer truck
58 // 59
5.2 Auger conveyor
Unlike the belt conveyor, the auger remixes the
concrete and prevents segregation of the concrete
mix.
The hydraulically operated auger conveyor offers
the same options of flexible adjustment and
mounting as the belt conveyor.
In addition, the auger can be adjusted to a steeper
incline – up to a maximum slope of 45°.
This feature permits both the paving of high
profiles and working on construction sites where
space is limited.
Its large diameter of 400 mm (16”) enables the
auger to act as a material buffer, offering capacity
for holding extra concrete quantities.
The auger can hold sufficient material for contin
uous delivery of concrete into the mold during
changes of concrete mixer trucks or when paving
in tight radii, thus minimizing breaks in the paving
operation.
The auger conveyor is ideal for use on sites where space is limited
The rotating auger remixes the concrete during conveyance
60 // 61
5.3 Cross-feeding
Certain slipform paver models are suitable for
fitting with a cross-feeding or transverse auger,
which ensures even greater flexibility for the
paving of concrete profiles.
The cross-feeding auger is useful, for instance,
when the mold is mounted far to one side of the
machine frame and the concrete mixer and paver
must travel in one lane. In this case, the concrete
The cross-feeding auger increases flexibility on site
is delivered to the primary conveyor, forwarded
to the cross-feeding auger and finally transported
into the offset mold.
The cross-feeding auger is capable of feeding
to the left or to the right, depending on the
arrangement of the paving mold. It can be
adjusted to either side hydraulically and can be
used as a material buffer.
The cross-feeding auger can be adjusted to reach the mold position
The concrete is transported right into the hopper
62 // 63
5.4 Dumping the concrete mix in front of the paver
Slipform pavers are also suitable for the production of roads, bicycle paths or similar concrete
pavements. The concrete can be transported via
conveyor, but can also be dumped on the ground
ahead of the slipform paver.
5.5 Chute and hopper
The delivery of concrete from the mixer to the
conveyor is effected at the lowest point of the
feeding system. The concrete is then transported
up the conveyor to the mold via a chute and
receiving hopper. The hopper provides head
pressure and a vibration chamber which ensure
that the mold profile will fill and that adequate
compaction takes place.
Chute at the auger conveyor
Delivery of concrete from the pivoting chute of the conveyor into the hopper
64 // 65
5.6 Push bar
A paver pushing a transit mixer
The transit mixer can be rigidly connected to the
slipform paver by means of a connecting bar.
The steady distance between the two machines
guarantees clean, continuous delivery and
prevents material losses. The paver pushes the
mixer truck, which is gentle on the truck’s clutch
and makes work easier for both the truck driver
and the ground crew. It is also not necessary to
familiarize the mixer driver with the distance he
needs to maintain from the paver.
66 // 67
6
Concrete slipforming / Molds
6.1
Mold function and design 72
6.2
Mold options 74
6.3
78
6.3.1
Combination mold 78
6.3.2
Curb depressor
80
6.3.3
Sideplates
81
6.3.4
Mold mounts
82
6.3.5
Adjustable mold mount 84
6.3.6
Quick-change mold mounting system
86
6.4
Basic classification of different mold types 88
6.5
Special molds 90
68 // 69
Molds give the concrete its final shape and provide
the required contact pressure.
Countless different profiles can be produced –
either standardized or to customer specification.
70 // 71
6.1
Mold function and design
Finished
concrete profile
Profile form
Hopper
Housing
Sideplate
Subgrade level
Components of a concrete mold
The receiving hopper of the concrete mold
accepts the concrete delivered by the feeding
system.
The hopper needs to hold a certain quantity of
concrete all the time during the entire paving
operation in order to be able to exert head
pressure on the concrete being formed.
The concrete fed into the mold is compacted by
means of vibrators, and then takes shape in the
mold through the continuous advance movement
Concrete
feeding
Concrete compaction
Concrete forming
Shape of the finished
product
Cross-section of a mold
of the slipform paver. Hydraulic sideplates can be
used to compensate for irregularities in the subgrade. They additionally prevent concrete blowout
and yield loss. Prior to being given its final shape
in the slipform pan, the concrete profile is given a
surface finish. The finished concrete
profiles typically have high degrees of stability,
close tolerances, smooth surfaces and high
production. In addition, the molds can be mounted
to allow for inset or offset paving.
72 // 73
6.2
Mold options
Curb
Curb and gutter
Water gutter
Curb and gutter
74 // 75
6.2
Mold options
U-shaped canal
V-shaped canal
Traffic barrier
Slab
76 // 77
6.3
6.3.1
Combination mold
Basic mold body
Upper part of mold
Spindle for adjusting
the housing width
Guide of sideplate
(adjustable)
Guide of sideplate (rigid)
Guide plates
End piece of mold insert
Mold insert 3
Mold insert 1
Mold insert 2
Finished
concrete profile
Design of a combination mold
Combination molds comprise a basic mold
body and various mold inserts for separate
insertion. The different working widths and
geometries of the inserts enable the mold to
be used for a wide variety of applications.
The combination mold can be a cost-effective
alternative. The mold inserts have working widths
ranging from 250 mm to 1,100 mm (10” to 3’7”)
and various paving thicknesses.
The different mold inserts are interchangeable,
permitting a canal profile, for instance, to be
replaced with a curb and gutter profile or vice
versa.
A spindle enables the adjustable (inner) sideplate to be moved manually so that the distance
between the two sideplates equals the working
width of the mold insert to be used. The hydraulic
clamping unit telescopes out, is placed behind the
guide plates of the mold insert and pulls the mold
insert back between the guide rails towards the
mold hopper. The system is sealed by the contact
pressure exerted by the clamping unit.
The adjustable sideplate is then pressed against
the mold insert so that the insert is positively
locked into the mold body.
The separate end piece for fine alignment of the
mold is bolted to the guide plates and aligned.
Production of a curb and gutter profile using a combination mold
78 // 79
6.3
6.3.2
Curb depressor (driveway knife)
The plate is hydraulically lowered into place in the
flattened section
Gently rounded curb edges
Continuous curbs frequently need to include
flattened sections to facilitate access to driveways
or parking lots. Using two different molds for this
job would involve significant effort.
A lowering plate or rotating plate is therefore
used in the flattened sections which keeps the
concrete out of the curb section of the mold but
allows concrete to fill the gutter portion. The plate
is raised again when returning to paving the curb
at full height.
This feature is called curb depressor or driveway
knife.
“Undepressed” curb
“Depressed” curb
Curb depressor
(plate pressed down)
Operating principle of the curb depressor
Mold
6.3.3 Sideplates
Hydraulic cylinders press the sideplates down on the subgrade
Hydraulic sideplates are used to minimize the
quantity of concrete leaking out from the mold and
to ensure clean finished edges of the concrete profile. The sideplates are hydraulically pressed down
on the subgrade, sealing the mold at the sides.
Concrete loss is minimized
80 // 81
6.3
6.3.4
Mold mounts
Mold mounted on the left side of the paver
The mold can be mounted on either the left or
right side of the paver. A telescoping mold mount
enables the mold to be shifted to the required
horizontal position.
Mold mounted on the right side of the paver
82 // 83
6.3
6.3.5
Adjustable mold mount
Mold positioned inside a trench
Hydraulic height adjustment allows the mold to be
adapted to conditions on the construction site and
to be easily lowered below grade.
Avoiding obstacles, such as manhole covers, is
just as easy. The height can be adjusted within a
range of 400 mm (16”).
Mold lowered below grade
84 // 85
6.3 Additional functions
6.3.6 Quick-change mold mounting system
Offset molds can be connected or disconnected
quickly and easily using the optional quick-change
system. To do so, the paver drives up to the mold
in order to slide mounting hooks into guides on the
mold. The mold is then secured to the mold mount
by means of the hydraulic clamping tool.
Step 1: Drive up to the mold
Step 2: Lower the attachment plate with mounting hooks
Step 3: Slide mounting hooks into guides on the mold
Step 4: Secure mold with hydraulic cylinders
86 // 87
6.4 Basic classification of different mold types
Type of mold
Type 1
Type 2
Base
level, prepared
unprepared
Trimmer
not required
required
Hydraulic sideplate
required
not required
A distinction is generally made between two differ
ent mold types:
Type 1 is used on a previously prepared, level
base. Hydraulic sideplates provide clean finished
edges. The machine is therefore not equipped with
a trimmer. Type 2 is equipped with a trimmer to
fine trim the grade prior to the paving operation.
The fine trimmed grade dispenses with the need
for hydraulic sideplates and maximizes concrete
yield.
Type 1 mold without trimmer
Type 2 mold with trimmer
88 // 89
6.5
Special molds
This application involves the production of a curb
with rainwater drainage pipe. The hollow space is
created by an air-filled rubber hose that is ventilated and removed after hardening of the concrete.
The polystyrene boards inserted manually to form
the drainage slots are removed after the concrete
has hardened for 5 to 6 hours.
Polystyrene boards
Rubber hose
Rainwater drainage pipe
Curb
This application involves the extension of an
existing concrete profile. Stringline is not required
as the existing profile can be used as a template
for paving the new one.
New profile
Existing profile
90 // 91
6.5
Special molds
The hydraulically height-adjustable sideplates
permit easy adjustment to different depths.
The sideplates always precisely adjust to the
contour of the trench.
Canal mold with
adjustable sideplate
Previously
excavated trench
The surroundings of the construction site – like
the hillside shown on the left – sometimes prevent
the paver from driving right up to the paving site.
This special design with modified support frame
and chute enables paving of a water canal at a
significant offset from the machine.
A counterweight should additionally be fitted on
the opposite side of the paver.
Support frame
Water canal
92 // 93
6.5
Special molds
In this application, the slipform paver is towing
a profile that is rigidly mounted inside the mold
during the paving operation.
The process dispenses with the use of support
pipes that would have to be removed later in a
separate operation, and creates a continuous
hollow space inside the profile.
Polystyrene board
Slot gutter
Towed steel profile
Removable polystyrene boards are inserted into
the slot created by the mold above the pipe during
the paving operation. To stabilize the profile, the
slot is bridged manually at defined intervals.
The finished profile will be used for the drainage of
a pavement to be constructed at a later date.
Polystyrene board
Slot gutter
Towed steel profile
94 // 95
7
Concrete compaction
7.1
100
7.2
Vibrator designs
102
7.2.1 Straight vibrators
102
7.2.2
Curved vibrators 102
7.3 Types of vibrator operation
103
7.3.1 Electric vibrators
103
7.3.2
Hydraulic vibrators
103
7.4 Theoretical effective vibrator radius
104
106
7.5.1 Offset applications 106
7.5.2
Slab paving
108
110
96 // 97
Offset profiles will meet the specified requirements
only when good compaction of the concrete in the
mold is ensured. Concrete vibrators are therefore
placed inside the hopper to homogeneously com-
pact the fresh concrete mix by means of vibration.
A wide variety of concrete vibrators is available,
differing in design, type of drive and size.
98 // 99
7.1
The fresh concrete mix fed into the hopper contains a varying percentage of voids, depending
both on the consistency and type of aggregate
used. These air-filled voids need to be removed
in order to give the fresh concrete the required
properties, such as suitability for slipforming and
strength.
on the specific application. Continuous advance
movement of the paver is yet another prerequisite
for the production of structurally sound concrete
profiles.
Vibrators contain an eccentric weight which is
attached to the vibrator shaft and caused to vibrate as a function of increasing vibrator speed.
During the compaction process, the high-frequency concrete vibrators then transfer these vibrations
to the concrete.
This causes the air in the concrete to rise to the
surface and escape, and the voids to close.
Despite compaction taking place, the vibrating
concrete mass is characterized by improved flow
properties, thus ensuring the creation of a homogeneous concrete profile. This process is
also called concrete liquefaction.
Expert’s tip:
• Thoroughly clean the vibrators and vibrator
suspension after completion of the paving
operation! A soiled vibrator suspension results in the vibrator not being able to vibrate,
leading to increased power consumption and
possible vibrator failure.
The concrete needs to be compacted uniformly
across the entire cross-section; non-compacted
areas need to be avoided. The vibrators are
therefore arranged at defined intervals depending
Poor concrete quality because of an excessively high
content of air voids
High concrete quality because of a low content of air
voids and homogeneous grain size distribution
Plug
Smooth protective tube inhibits “caking” of concrete
Fully potted connections
to ensure mechanical
damage protection,
safe insulation and heat
dissipation
Internal vibrator geometry prevents
protective tube from being damaged
by vibrator suspension
Integrated three-phase
induction motor
Large effective radius and high
compactive power due to high
eccentric force
Special roller bearings
Components of an electrical vibrator
100 // 101
7.2
Vibrator designs
7.2.1
Straight vibrators
Straight vibrators are mostly used for offset
paving, especially when creating high or upright
structures, such as traffic barriers or curb and
gutter profiles. Their small, slim suspension
enables straight vibrators to ensure smooth
concrete flow in the receiving hopper.
7.2.2
Curved vibrators
Curved vibrators are generally used when paving
concrete slabs, and are mounted in the compaction zone in front of the mold.
7.3
Types of vibrator operation
7.3.1
Electric vibrators
Electric vibrators have passed the test in concrete
slab paving. Each single vibrator in the system can
be monitored electrically, and an alert is displayed
in case of a vibrator failure. These features ensure
optimum and controlled concrete compaction.
Electric vibrators are driven by a three-phase
induction motor, which makes them highly
efficient, economical in operation and relatively
maintenance-free.
7.3.2
Hydraulic vibrators
Hydraulic vibration is particularly suitable for offset
applications, such as the production of curb and
gutter profiles or traffic barriers.
Especially when paving profiles of complex geometry, the vibrators need to work the concrete in
the different zones at different degrees of intensity.
Not only can the frequency of each individual
hydraulic vibrator be adjusted separately, but the
vibrators can also be adjusted to concrete
of varying consistency.
Expert’s tip:
• Electric vibrators are ideally suited to the
paving of concrete slabs, especially because
of their high efficiency and simple frequency
control.
• Operate the vibrators only when immersed in
the concrete inside the receiving hopper.
102 // 103
7.4
Theoretical effective vibrator radius
The effective radius of a vibrator for concrete
compaction can best be described as resembling
a cone-shaped structure enclosing the vibrator
shaft. Variations in the vibrating frequency lead
to corresponding alterations in the base of the
cone – the effective radius – and thus of the entire
effective compaction area.
Vibrator
Vibrator
Effective
radius
Effective
radius
Effective radius at low vibrating frequency
Effective radius at high vibrating frequency
To ensure full, homogeneous concrete compaction, the vibrators need to be installed in the
hopper at regular intervals. The level of concrete
in the compaction zone, or in the hopper respectively, also plays an important role. The concrete in
the hopper needs to exert a head pressure in order
to achieve full compaction and to fill the mold
adequately.
When paving concrete slabs, the level of concrete
above the mold – depending on the position of the
vibrators – should equal approximately half the
thickness of the concrete slab to be built.
An approximation formula for determining the
theoretical effective vibrator radius estimates the
diameter of the effective radius to be approximately ten times that of the vibrator.
A sufficient level of concrete needs to be ensured
at all times in the hopper, therefore, when paving
offset applications.
Vibrator
d
Effective radius
D = 10 x d
104 // 105
7.5.1 Offset applications
The vibrators need to be positioned correctly
to ensure optimum compaction of the concrete
mix. They are installed with their longitudinal axis
pointing in the direction of the material flow, their
number and arrangement depending on concrete
consistency as well as the size and type of profile
to be paved.
As a rule, the vibrators need to be installed at such
intervals as to ensure overlapping of their effective
radii to prevent any non-compacted areas remain
ing in the concrete after compaction.
The following applies for offset paving
applications:
Position the vibrators inside the hopper.
elect the number of vibrators in accordance
S
with the cross-section of the profile.
Ensure overlapping effective vibrator radii.
aintain a consistently high concrete level in
M
the hopper to ensure uniform degrees of compaction and evenness.
osition the vibrators so as to prevent collision
P
with any concrete reinforcement.
The vibrators effect concrete compaction
Overlapping effective vibrator radii
106 // 107
7.5.2
Slab paving
The following applies for slab paving
applications:
Position the vibrators in front of the mold.
he concrete mix needs to be compacted
T
uniformly and fully across the entire crosssection of the slab. To ensure adequate
compaction, adjust the internal vibrators at
the same height and to the same direction
across the entire paving width.
Install the vibrators at regular intervals in order to
prevent non-compacted areas remaining in the
concrete.
The vibrators are arranged at regular intervals
he first vibrators on the left and right are usually
T
installed at a distance of around 125 mm (5”)
from the side of the mold. The remaining vibrators should then be installed at intervals ranging
from 360 mm to 380 mm (14” to 15”).
It is vital to maintain a consistently high filling
level of concrete in the compaction zone in
order to ensure high quality of compaction and
evenness.
~125 mm
~ 360 380 mm
~ 360 380 mm
Overlapping effective vibrator radii
108 // 109
Sirometer for frequency measurement
The compactive power to be provided by the vi
brators depends on a number of parameters, such
as consistency of the concrete mix or the type of
aggregate used. To achieve adequate compaction, the vibrator shaft should work within a speed
range of between 7,000 and 12,000 revolutions per
minute (rpm).
The speed of vibrators is measured by means of a
resonance-revolution-frequency meter. The device
measures the vibrator frequency with an adequate
degree of precision, working within a tolerance
range of approximately +/- 2%.
It has a measuring range of 800 to 50,000 revo
lutions per minute (rpm), equaling approximately
14 to 833 Hz.
To determine the frequency, the device is placed
against the vibrator’s protective tube during the
paving process. Turning the upper part of the
frequency meter to the left will extend the pilot
wire. At a certain extended wire length, the end of
the pilot wire will be excited to vibrate in its natural
frequency (resonance). After setting the sirometer
to the greatest amplitude, the mark on the upper
scale will show the current speed per minute (rpm).
The lower scale will show the current number of
vibrations per second (Hz).
110 // 111
8
Curing
8.1
Weather protection
116
8.1.1
Treatment with curing compounds
116
8.1.2
Curing blankets
118
8.1.3
Continuous moistening with water
119
8.2 Cutting joints
120
8.2.1 Contraction joints
120
8.2.2
Expansion joints
122
8.3 Sealing joints
123
8.4
Concrete testing methods
124
8.4.1 Testing fresh concrete
124
125
8.4.1.2
Determining the air content by means
of the pressure gauge method
134
8.4.2 Testing hardened concrete
136
112 // 113
As concrete cures, its volume decreases – it
shrinks. Unless precautions are taken to maintain
the required water content during the hydration
process, stresses will occur in the concrete
that can lead to excessive cracking.
Weather conditions can have a significant effect,
too. Drying of the concrete surface is accelerated
at higher ambient air temperatures or exposure
to sunlight. Freshly placed, exposed concrete
additionally needs to be protected from exposure
to rain, wind, sun and frost.
The curing period is largely dependent on the
intended use, composition and strength development of the concrete, temperature of the concrete
and ambient conditions.
Because concrete shrinks during hydration even
when properly protected, joints need to be cut
into the hardening concrete at defined intervals
to prevent uncontrolled cracking.
114 // 115
8.1 Weather protection
8.1.1 Treatment with curing compounds
Curing compound creates a thin protective film on
the surface of concrete that prevents evaporation
of the water during the early hydration process.
Curing fluids are liquid, paraffinic compounds
characterized by a high barrier coefficient, which
significantly reduces evaporation of water at the
concrete surface after spraying.
The pores of concrete surfaces sprayed with a
curing compound are sealed by means of wax.
As a result, the water is retained in the concrete
which then hydrates in a steady process.
High-pressure spraying pump
The curing compound is applied to the concrete
surface evenly by means of a suitable spraying
device. High-pressure spraying pumps are ideally
suited to curing offset profiles or small concrete
slabs. The use of self-propelled curing machines
with automatic spraying systems is more practical
for the curing of larger pavements.
The curing compound needs to be applied across
the entire surface and as early as possible after the
bleed water sheen has disappeared.
Apply the curing compound as evenly as possible
Great care should be exercised to ensure that
a continuous film is created and the spraying
quantity specified by the manufacturer is adhered
to. The amount of curing compound sprayed can
be checked by means of a simple test. To do so,
a clean sheet of paper in DIN A4 size is weighed,
placed on the concrete surface to be cured and
then weighed again after spraying. The difference
in weight equals the amount of liquid absorbed by
the sheet of paper.
Vertical surfaces may sometimes require repeated
spraying. The curing compounds are usually mixed
with light-coloured pigments which reflect sunlight
and make it easy to determine to what extent and
how evenly a surface has been sprayed.
DIN A4 = 0.21 m x 0.297 m = 0.06237 m2
Expert’s tip:
0.06237 m2 x 16 = 1 m2
• A standard sheet of paper in DIN A4 size and
a standard letter scale can be used to check
the quantity of curing compound sprayed.
The resulting difference in weight multiplied by
16 equals the quantity of curing compound
sprayed per square meter of concrete surface.
Test to determine the required spraying quantity
116 // 117
8.1 Weather protection
8.1.2 Curing blankets
Freshly placed concrete slab covered with a polyethyl
ene film
A cover of canvas tents
Covering concrete surfaces with polyethylene film
is frequently done to protect against excessive
surface evaporation. The films need to be placed
on the slightly moist concrete with an overlap.
To prevent air entering between the concrete
surface and the cover, dehydrating the concrete,
great care needs to be taken that the sheets are
firmly fastened at their edges, for instance, by
means of adhesive tape.
When covering concrete surfaces with watersaturated materials, such as burlap, straw mats or
layers of sand, the covering needs to be kept just
as moist and, if necessary, needs to be protected
against an excessively fast release of moisture by
covering it with an additional polyethylene film.
Mobile, folding canvas tents have also proven
highly suitable for covering concrete slabs.
These protect from exposure to both sun and rain
but not from evaporation.
8.1.3 Continuous moistening with water
Moistening concrete surfaces with water is yet
another frequently applied measure to avoid excessive surface evaporation. The concrete surface
needs to be kept moist all the time, for alternating
moistening and drying can lead to stresses and
thus cracking in the fresh concrete. Texture curing
machines are well suited for applying water.
Direct splashing of the concrete with a strong jet
of water needs to be avoided as sudden cooling
of the concrete surface may cause cracking in the
concrete structure. In addition, cement paste can
be washed out, which may have an adverse effect
on the strength of the aggregate structure in the
area of the slab or profile surface.
Curing with moisture is not permitted at temperatures below freezing; a thermal insulation usually
needs to be provided as a cooling protection
instead. Additional measures are required in case
of high ambient temperatures, exposure to direct
sunlight, extremely windy conditions or extremely
low temperatures.
Moistening concrete by means of a texture curing machine
118 // 119
8.2 Cutting joints
The natural – practically uncontrolled – formation
of cracks in concrete needs to be prevented so
as not to have an adverse effect on the usability
and service life of concrete structures. Concrete
has a relatively low tensile strength. Artificial joints
are therefore cut at defined intervals to avoid wild
8.2.1 cracks and to gain control of the cracking process.
A general distinction is made between contraction
joints and expansion joints. Contraction joints
are important for limiting the cross-section of the
profile, while expansion joints cut the structure into
entirely separate parts.
Contraction joints
Diamond cutting disc
Diamond cutting disc
Contraction joints are predetermined breaking
points in the concrete profile. After hardening of
the concrete, a groove is cut into the surface of the
profile’s cross-section to weaken it, thus provoking
the controlled formation of a crack at the defined
position.
the surfaces of the crack is adequate to permit the
transmission of forces between the separate parts
of the structure.
The anticipated crack is intended to propagate
down the entire depth of the section at this point.
Experience has shown that the natural interlock of
A diamond cutting disc is used to cut a 2 cm
to 3 cm (0.8” to 1.2”) deep groove across the
entire cross-section of the concrete profile.
Intervals between the joints range from 4.5 m to
10 m (15’ to 33’) as specified.
On the one hand, the joints need to be cut
sufficiently early to prevent any tensile stresses
occurring in the hardening concrete.
On the other hand, the concrete needs to have
hardened sufficiently to allow clean cuts without
material disruptions. Joints can therefore be cut
within a few hours after completion of the paving
operation at high ambient temperatures, and within
one or two days in cooler weather.
For some applications, joints may be formed by
pressing tools into the still wet concrete.
Expert’s tip:
• Exercise great care when beginning to
cut the joint in the upper section of the
concrete profile, and then slowly continue
with a vertical, downward cut!
• Do not allow the concrete to harden ex
cessively so as to be able to make a clean
cut! Make a test cut approx. 2 to 6 hours
after the paving operation (depending on
weather conditions) to establish the sawing
window!
• Take care not to tear out any part of the
concrete structure during cutting; be sure to
produce a clean cut surface instead!
• Use a water spray system during cutting in
order to reduce the development of dust!
• Watch out for any reinforcement!
120 // 121
8.2 Cutting joints
8.2.2
Expansion joints
Cutting expansion joints with a chain saw
Expansion joints are required when paving long,
continuous concrete sections, or when concrete
profiles encounter permanent fixtures, such as
bridge structures. The concrete sections are
separated by a gap, which permits expansion of
the separate parts of the profile.
Fully separated traffic barrier
8.3 Sealing joints
The joints to be sealed need first to be cleaned.
To prevent leaks and resulting damage to the concrete structure, joints are pre-treated with primer.
They are then filled with a joint sealing compound,
such as silicone. An alternative option is the use
of a compressible joint profile that is pressed into
the gap. The sealing compound limits ingress of
water and other impurities into the joint. Sealing of
the joints should be carried out in dry weather and
not at temperatures below freezing. The concrete
needs to have hardened to a sufficient degree.
Primer and joint sealing compound
Expert’s tip:
• Clean the cut joint by means of compressed
air, wet with primer, and fill with clean
silicone! Make sure to process any surplus
silicone as cleanly and quickly as possible
prior to hardening!
• Be sure to spread the joint sealing compound as evenly as possible inside the gap,
and to create a sealed surface when spread
ing the surplus silicone!
122 // 123
8.4 Concrete testing methods
A distinction is made between the testing of fresh
concrete and that of hardened concrete. Concrete
8.4.1
is considered to be fresh concrete as long as it is
suitable for processing and compacting.
Testing fresh concrete
Testing methods of fresh concrete which are of direct relevance for procedures on the construction
site include concrete consistency and air content.
Unless stated otherwise, the testing methods described in the following sections have been carried
out in accordance with German standards.
Experience shows, however, that European or
American guidelines are either identical with, or
at least comparable to, the German standards
applied.
Expert’s tip:
• Make sure for all concrete testing methods
that the specimens are placed on a stable,
horizontal base!
• Keep the measuring instruments clean, and
remove any remaining concrete material after
each test!
• Perform all measurements immediately after
sampling!
Definition of consistency:
As the workability of concrete is not a physical
term but an unknown combination of the properties of flowability, deformability and compactability,
it is not possible to give an unambiguous physical
definition or perform an unambiguous physical
test. In addition, there is the fact that fresh
concrete is in a plastic state during transport, in
a liquid state during mixing and compacting, and
temporarily in both states during paving.
The mixed term of consistency is therefore used
for a quantitative assessment of concrete com
pactability.
Consistency range
very stiff
According to DIN 1045-2 / DIN EN 206-1, the
consistency of fresh concrete is divided into the
following categories: very stiff, stiff, plastic, soft,
very soft, fluid and very fluid.
Within the boundaries of these categories, the
consistency is indicated more precisely by a
degree of consistency in accordance with the
table below.
Flow consistency classes
Degree of compactability classes
Class
Flow consistency
[mm]
Class
Degree of
compactability [v]
–
–
C0
≥ 1.46
stiff
F1
≤ 340
C1
1.45 – 1.26
plastic
F2
350 – 410
C2
1.25 – 1.11
soft
F3
420 – 480
C3
1.11 – 1.04
very soft
F4
490 – 550
fluid
F5
560 – 620
very fluid
F6
≥ 630
124 // 125
The most important, internationally most commonly used consistency testing methods are explained
in some detail below. The tests merely consider
the self-weight of the concrete mix, however, and
do not reflect the dynamic processes occurring
during the paving operation.
Flow table test in accordance with
DIN EN 12350-5
A frustum of a cone is placed on a previously
moistened flow table. The fresh concrete is filled
into the cone in two layers, each of which is compacted by gently tamping ten times using a wood
en pestle. Following removal of the cone, which is
lifted vertically, the flow table is smoothly raised all
the way and dropped again 15 times within
15 seconds. The diameter of the spread-out
concrete cake is then measured in two directions
parallel to the edges of the flow table.
Fill in fresh concrete
The arithmetic mean of both measurements is the
flow consistency a. The concrete cake should have
a regular shape and closed surface.
The flow table test is particularly well suited for
concretes of the soft to very fluid consistency
ranges, but is not suitable for stiff or very stiff
concretes.
a=
Remove cone
d1 + d2
2
Raise and drop the flow table
Determine the flow consistency
126 // 127
Degree of compactability test in accordance
with DIN EN 12350-4
The fresh concrete is filled into a 400 mm high
metal container that is open at the top and has
a cross-section of 200 mm x 200 mm (or into a
200-mm cube-shaped container with 200-mm
supporting frame) without compaction. A trowel
is used for this purpose, and the concrete is filled
into the container via one of the trowel’s longi
tudinal edges. Any surplus concrete is struck off
to achieve a level surface. After that, the concrete
is compacted to the maximum degree possible
using a vibrating table and an internal vibrator or
a tamping device. The degree of compactability
v is calculated as the ratio of the height of the
non-compacted concrete h to the height of the
concrete after compaction h-s (arithmetic mean
obtained by measuring at the four corners of the
container in mm):
This testing method is suitable in particular for
concretes of the very stiff, stiff and plastic con
sistency ranges.
Fill in fresh concrete
Vibrate container filled with concrete
h
400
V=
=
h–s
400 – s
Fully compacted concrete
Measure the height of the concrete in the container
128 // 129
Slump test in accordance with DIN EN 12350-2
The fresh concrete is filled into a frustum of a
cone, which has a height of 300 mm, top diameter
of 10 cm and base diameter of 20 cm, in three
layers of approximately equal volume. Each layer
is compacted with 25 strokes, using a tamping rod
weighing 1.5 kg. The metal cone is lifted vertically
five to ten seconds after filling. The maximum
height of the slumped concrete cone is measured
immediately after removal of the mold.
The slump is calculated as being the difference
between the height of the mold and the height of
the concrete cone after removal of the mold.
The slump can be determined by means of a table
which is divided into the classes S1 to S5 with
slumps ranging from 10 mm to more than 220 mm.
The total duration of the test should not exceed
two and a half minutes.
Fill the mold to one third of its height
Compact concrete layer
The slump test is particularly suitable for concretes
in the medium consistency range.
Lift slump cone vertically upward
Measure difference in height
130 // 131
Vebe test in accordance with DIN 12350-3
The fresh concrete is filled into a frustum of a cone
and compacted. The cone has a height of 30 cm,
a top diameter of 10 cm and a base diameter of
20 cm, and has been placed inside a 24-cm
cylindrical container. After removal of the slump
cone, the concrete is remolded from the shape of
a frustum of a cone to the shape of the cylindrical
container while being exposed to the simultaneous
action of a standardized vibrating table and an
imposed load. The degree of consistency is the
time in seconds needed for this remolding process
to take place.
Fill in fresh concrete and compact
Lift slump cone vertically upward
This testing method is suitable mainly for stiff to
plastic types of concrete.
Apply load and vibrate
Measure time needed for complete remolding
132 // 133
8.4.1.2 Determining the air content by means of the pressure gauge method
As specified by DIN EN 12350-7, the pressure
gauge method uses a sealed container to test the
air content of fresh concrete. The measurement is
based on the fact that the volume of the air contained in compacted concrete will change when
exposed to positive pressure.
Fresh concrete is filled into the container and
compacted. The container is sealed, and posi
tive pressure is generated in the pressure vessel.
A wash bottle is used to inject water into the
container through valves, filling the space between
the concrete and the container lid. The valves are
closed, and the positive pressure is released into
the concrete sample via a third valve.
Fill in fresh concrete and compact
The air content can now be directly read off at the
pressure gauge. Establishing the air content of the
fresh concrete enables determination of the frost
resistance of the hardened concrete structure.
The air content describes the volumetric percent
age of air voids in a fully compacted concrete.
Concretes not containing any air-entraining agents
usually have air contents of 1% to 2% by volume.
The overall air content of autoclaved aerated
concretes is higher due to artificially entrained air
voids. Resulting side effects are improved co
hesion and workability of the fresh concrete,
and frost resistance of the hardened concrete
structure.
Inject water
Release positive pressure
Read off air content
134 // 135
8.4.2
Testing hardened concrete
Compressive strength is the most important
property of concrete, and testing the compressive
strength as specified by DIN EN 12390-2 is the
most commonly applied method of testing
hardened concrete. Country-specific regulations
usually stipulate the testing of specimens for
strength assessment. Based on the compressive
strength determined by testing, the concrete can
be classified into the different strength classes.
Step 1: Making the specimens
The national German standard goes on to
specify:
In Germany, cubes with an edge length of 150 mm
are the type of specimens most frequently used for
compressive strength testing. International testing
procedures commonly use cylinders with diameters of between 100 mm and 150 mm and a height
to diameter ratio of 2:1. Especially in the United
States, compressive strength testing is carried out
using cylinders with a height of 152 mm (6”) and a
diameter of 305 mm (12”).
Fresh concrete is filled into the mold in at least
two separate layers of ≤ 100 mm thickness each
and compacted. Compaction is carried out using
internal vibrators, a vibrating table or tampers
(25 strokes per layer). Vibrating needs to continue
until the development of larger air bubbles at the
surface has lessened considerably. If the concrete
is compacted by tamping, the spatula needs to be
poked downward between the concrete and the
inner walls of the mold after filling to allow any air
sticking to the walls to rise to the surface and escape. Regardless of the type of compaction used,
the surface should be struck off after compaction
so as to achieve an as level and smooth surface as
possible.
eep test specimens at (20 ± 2) °C for
K
(24 ± 2) hours after making, and protect
against drying
emove test specimens from the molds after
R
(24 ± 2) hours
lace demolded test specimens on shelf supP
ports in the water bath or on a shelf tray in the
curing chamber at > 95% relative humidity, and
store at (20 ± 2) °C for 6 days until the time of
testing
lternatively, store test specimens at
A
(20 ± 2) °C and (65 ± 5) % relative humidity
from day seven after making until the time of
testing; with this procedure, the tested strength
needs to be reduced by a defined factor
Making test specimens
Test specimens in the water bath
136 // 137
Cube-shaped specimen clamped into the testing
apparatus
Fractured test specimen
Step 2: Testing the specimens
The load surfaces of test specimens need to be
smooth and run parallel to one another. When
using cube-shaped specimens, the load is applied
perpendicular to the direction of filling and at a
speed of approx. 0.5 N / (mm² x s).
fc - compressive strength
F - maximum strength
at failure
Ac- cross-sectional area
of specimen
The compressive strength is calculated using the
following equation:
For cubes with an edge length of 150 mm, the
compressive strength of concrete after storing in
a water bath (fc,cube) needs to be specified with an
accuracy of 0.5 MPa (N / mm²). If the cubes are
stored in line with DIN EN 12390-2, Annex NA
(“dry storage”), the tested strength fc,dry needs to
be converted to the reference storing method
(storing in water bath) according to the following
table:
F
fc =
Ac
[MPa] or [N/mm2]
[N]
[mm2]
Compressive strength class
Cube, 150 mm
Ordinary concrete ≤ C50 / 60
fc,cube = 0.92 x fc,dry
High-strength ordinary concrete ≥ C55 / 67
fc,cube = 0.95 x fc,dry
The ready-mixed concrete manufacturer will
confirm, as part of his monitoring services, the
“conformity” of his production with the specified
compressive strength. The building contractor will
check the “identity” of the concrete mix supplied
with the “conforming” parent population (identity
test or monitoring test). At least three samples of
each concrete mix to be processed need to be
taken on the construction site.
Common testing methods and guidelines applied
in the United States include:
„Air Content of Freshly Mixed Concrete by the
Pressure Method“
ASTM C 231 / AASHTO T 152
„Air Content of Freshly Mixed Concrete by the
Volumetric Method“
„Density (Unit Weight), Yield, and Air Content
(Gravimetric) of Concrete “
„Specification for Compressive Strength“
„Specification for Flexural Strength Using
Third-Point Loading“
„Specification for Flexural Strength Using
Center-Point Loading“
„Specification for Splitting Tensile Strength“
138 // 139
9
Concrete reinforcement
9.1
Basics of concrete reinforcement
144
9.2
Types of concrete reinforcement
146
140 // 141
Concrete is characterized by high compressive
strength, but offers only very limited resistance
to tensile forces. Steel is therefore inserted in
the concrete to absorb any tensile stresses or
additional compressive forces.
142 // 143
9.1 Basics of concrete reinforcement
As concrete is capable of absorbing only very
limited tensile and bending forces, steel is inserted
in the concrete structure to absorb these forces.
Combining concrete and steel also increases the
material’s resistance to additional compressive
action.
Steel reinforcements embedded in concrete structures are usually well protected from corrosion,
thus eliminating the need for additional protective
measures. The high alkalinity of the enveloping
concrete causes the steel to develop a thin,
continuous oxide skin. The concrete also keeps
the reinforcement firmly in the required position to
compensate, in the best way possible, any forces
acting on the concrete structure from the outside.
Concrete reinforced by means of steel is called reinforced concrete. The special concrete reinforcement used for this purpose is called reinforcing
steel. Common types of concrete reinforcement
include steel bars, steel mats or wire meshes.
The type of reinforcement to be used is generally
specified by the tender authorities.
The molds can be designed so as to permit prefabricated steel reinforcements to be introduced
into the concrete without difficulty. Corresponding
guides are provided in the front part of the mold
to accommodate continuous steel ropes or steel
bars.
F tensile force concrete
F tensile force steel
F tensile force steel >> F tensile force concrete
144 // 145
9.2 Types of concrete reinforcement
The amount of up to 10-m long steel bars required
for one day is placed on the course of the profile to
be paved, and the bars are welded together prior
to commencing the paving operation. The contin
uous reinforcement is then fed into the concrete
profile during paving. Safety barriers reinforced
with steel bars are even capable of withstanding
collisions with larger trucks. The steel reinforcement additionally prevents parts of the barrier
being knocked out and hurled onto the oncoming
traffic lane.
The 5-fold steel rope reinforcement gives the
traffic parapet a superior containment performance
level. The required lengths of steel rope are un
wound from reels prior to commencing the paving
operation, and are fed into the profile via centrally
arranged grooves during the continuous advance
movement of the slipform paver.
Wire meshes are continuous reinforcements
consisting of various reinforcing bars that are
interwoven, for instance, by means of wire ties,
metal loops or similar. They are customized to the
shape of the profile to be built, and are usually
poured in-situ as early as the preparation stage of
the base. Wire meshes integrated in traffic barriers
offer maximum containment performance levels as
specified, for instance, for bridge structures.
The continuous wire mesh reinforcement shown
here has been adapted to the shape of the canal
to be paved. The reinforcement is placed on
special supports prior to the paving operation,
enabling it to be integrated in the canal floor at
the specified height.
146 // 147
9.2 Types of concrete reinforcement
To increase the stability of concrete slabs, steel
mats are placed on special spacers prior to the
paving operation. Sections of steel mat are
connected by means of wire ties or welding.
The steel mats inserted in the concrete pavement
are capable of compensating the radial shear
forces generated in the narrow bends of round
abouts in particular by heavy trucks.
Steel tie bars are inserted manually at specified
intervals either by pouring them in-situ as early as
the preparation stage of the base or by embedding
them into the freshly produced concrete profile.
Their purpose is to firmly anchor a concrete profile
to the base or to connect two separately paved
concrete profiles. The tie bars are customized
to the particular shape of the profile to be paved
and can be designed, for instance, as bars or
U-sections.
148 // 149
10 Machine operation
154
10.2
Machine operation by means of stringline
156
10.2.1 Level control
156
10.2.2
Steering control
157
10.2.3 Machine behavior in relation to steering
sensor position when driving straight ahead 10.2.4
Machine behavior without additional steering sensor
when driving through outside radii 10.2.5
Machine behavior with additional steering sensor
when driving through outside radii 162
10.2.6
Machine behavior when driving through inside radii 164
10.3
Machine operation by means of a 3D system
166
10.3.1 Appraisal of the 3D control system
166
10.3.2
166
10.3.3
168
10.3.4
Functionality
170
10.3.5
Benefits
171
158
160
150 // 151
State-of-the-art slipform pavers are equipped with
automatic leveling and steering control systems.
The leveling control system governs the paving
thickness of concrete profiles in accordance with a
specified reference. When paving curved profiles,
for example, the steering control system detects
any changes in the reference and governs the
course of the profile accordingly.
the 3D control system feeds the paver’s control
system with the specified parameters of level and
horizontal position of the concrete profile to be
built. The 3D system uses a special interface to
communicate with the controller of the slipform
paver. The type of control system used depends
on the requirements and conditions prevailing on
the construction site.
A distinction is made between systems working
with stringlines and systems working without
stringlines. When using stringlines, sensors
guide off stringline during the paving operation,
communicating any changes to the paver’s control
system. With stringless systems, the computer of
Whereas systems using stringline have been
in widespread use to date, stringless systems
are gaining in market relevance. Handling of the
systems and their limitations are described in more
detail on the following pages.
152 // 153
Machine working without stringline – poor paving result
positioning of the stakes ensure that the specified
paving thickness and profile course are adhered to
with maximum accuracy.
An integrated control system is indispensable if
the slipform paver is to meet the specific requirements stipulated by tender authorities in terms of
paving accuracy. The requirements specified for
the results of the concrete paving operation are
available as theoretical basic information. Stringlines are frequently used to enable this information
to be used for paver operation and control.
Careful tensioning of the stringlines and precise
The stringlines are installed along the entire length
of the profile to be produced prior to commencing
work. They are frequently also required for the
preliminary work of preparing the base. Sensors
guide off the stringline during the paving operation,
communicating any changes in the paver’s position to the control system. A controller immediately
translates the information provided into a corresponding change in the paver’s steering angle
or chassis level. The range of suitable sensors
includes transducing sensors, slope sensors or
slab tracers.
With a 3D control system, an electronic measuring
device continuously tracks a bearing point (reflector) mounted on the slipform paver by means of a
laser beam. The measured results are forwarded
to the controller and constantly reconciled with
a digital terrain model. The controller initiates the
required corrections in level, slope and steering
angle of the crawler tracks.
Expert’s tip:
• Instead of using stringline, paving level and
direction can be copied from existing objects
or profiles using a slab tracer.
Machine working with stringline – good paving result
154 // 155
10.2 Machine operation by means of stringline
10.2.1
Level control
Level control using stringline
A stringline is carefully installed and tensioned
along the entire length of the concrete profile or
slab to be produced prior to commencing the
paving operation. It will provide the specified
paving level. Two separate sensors carried by the
slipform paver normally guide off the stringline
for level control – one sensor for the front crawler
tracks, a second one for the rear crawler tracks.
While the slipform paver keeps moving forward,
both sensors scan the stringline and continuously
send pertinent level details to the paver’s control
system. These level details are not absolute values,
however, but merely the deviations from the set
value that is provided by the stringline. The control
system receives the measured results, and in case
of any deviation actuates the relevant hydraulic
cylinders to compensate by adjusting the level of
the machine including the mold. This matching
process takes place around 40 times per second.
The side of the paver carrying the mold is
immediately raised or lowered by the resulting
difference between the actual and set values.
The opposite side of the machine is balanced in
level by means of a second control loop with integrated slope sensor.
Expert’s tip:
• The sensor should rest on the stringline so
as to preclude any risk of collision with the
stakes.
10.2.2
Steering control
Steering control using stringline
Parameters relating to the horizontal course of the
concrete profile to be produced are also obtained
by means of the previously installed stringline.
As before, two sensors carried by the slipform
paver guide off the stringline, and while the paver
keeps moving forward, both sensors scan the
side of the stringline and continuously send the
pertinent measured details to the paver’s control
system.
Here again, the measured results are merely the
deviations from the set value that is provided by
the stringline. The control system receives the
measured results, and in case of any deviation
actuates the relevant hydraulic cylinders via valves
to compensate by steering the paver’s crawler
tracks to the left or right. As before, the matching
process takes place around 40 times per second.
Expert’s tip:
• The steering sensor should be positioned so
that the stringline is in contact with the lower
third of the sensing probe.
• The larger the distance between the point of
contact and the suspension of the sensing
probe, the less precise the measurement will
be.
156 // 157
10.2.3
Machine behavior in relation to steering sensor position when driving straight
ahead
Finished
concrete profile
First steering
sensor
Small
distance
Second steering
sensor
Stringline
Minimum distance between steering sensors not maintained: risk of defective paving result
It is recommended to not position the steering
sensors too close to each other so as to ensure
optimal operation of the paver’s steering system
when driving straight ahead. Experience shows
that the two steering sensors should be installed
at a minimum distance of 1.5 m. Not maintaining
the specified minimum distance can result in a deviation from the ideal profile path, which is caused
by the control characteristics of the paver’s control
system: installing the sensors at an insufficient distance to each other bears the risk of overshooting
and thus a defective paving result.
Finished
concrete profile
First steering
sensor
Sufficiently large distance
Second steering
sensor
Stringline
Minimum distance between steering sensors maintained: optimum paving result
When driving straight ahead, an ideal position
for the first steering sensor is near the rear lifting
column, while the second steering sensor should
be installed as far to the front of the machine as
possible (see illustration above).
158 // 159
10.2.4
Machine behavior without additional steering sensor when driving through
outside radii
Stringline
Steering sensors arranged in the same way as when driving straight ahead
The ideal arrangement of the steering sensors
for driving straight ahead can be used without
difficulty for driving through outside radii with a
large radius. It is highly likely that the mold would
collide with the stringline, however, if the arrangement of the sensors were not changed when
driving through narrow outside radii. In addition,
the path of the mold and therefore of the concrete
profile would deviate from the set course as the
paver’s control system would alter the steering
direction of the front crawler tracks too early and
too extremely.
Stringline
Mold collides with stringline
160 // 161
10.2.5
Machine behavior with additional steering sensor when driving through
outside radii
Second steering sensor
Additional steering sensor
First steering sensor
Stringline
The front and rear steering sensors are in operation right before the radius
Switchover point 1
Stringline
The additional steering sensor and rear steering sensor scan the stringline in the radius
Stringline
Switchover point 2
The front and rear steering sensors are active again after exiting the radius
When driving through narrow outside radii, it is
recommended to integrate a third steering sensor
into the paving process and to install it ahead of
the second steering sensor. This permits simple
switching between the first steering sensor and the
additional steering sensor as required. The precise
position of the additional steering sensor depends
on the radius.
The additional steering sensor needs to be selected as soon as it has reached the tangent point of
the radius (switchover point 1). The new sensor
arrangement causes delayed steering of the front
crawler tracks so that the mold closely follows the
ideal set course of the profile as a result.
The first steering sensor needs to be reactivated
when it has returned to zero position at the exit of
the radius (switchover point 2).
As an alternative to using an additional, third steering sensor, the first steering sensor can be moved
to the position of the additional steering sensor at
the right time.
162 // 163
10.2.6
Machine behavior when driving through inside radii
Insi
de
rad
ius
Slipform paver collides with stringline
The sheer dimensions of slipform pavers prevent
them from performing arbitrarily small inside radii.
The minimum inside radius a machine is capable
of performing largely depends on the machine
configuration, such as the length of the paver or
distance of the mold from the chassis.
Ins
ide
rad
ius
Paving a profile when driving through an inside radius
The ideal arrangement of the steering sensors for
driving straight ahead can usually be maintained
when paving in inside radii. Care needs to be
taken, however, that the crawler track unit and
conveyor system will not collide with the stringline
when driving through the radius. Alternatively, the
front steering sensor needs to be moved forward
to the greatest extent possible to effect earlier
steering of the front crawler tracks.
Expert’s tip:
• A “dry run” can be performed in advance to
prevent collisions with the stringline during
the actual paving operation.
164 // 165
10.3.1
Appraisal of the 3D control system
Highly precise concrete paving using a 3D system
Construction machines like graders, cold milling
machines, asphalt pavers or slipform pavers
typically use mechanical systems for scanning
a stringline to effect horizontal position and level
control. Stringless 3D control systems have also
proven their worth in recent years, however, and
are sometimes even a requirement today in tender
specifications. 3D control offers many advantages
10.3.2
over stringline control – the ideal paving line,
for instance, need not be transferred to the actual
construction site by means of a wire but is
available as a computer model. Using this digital
terrain model plus an optical system comprising
a motorized total station and prism enables nearly
any given concrete profile to be produced stringless, with efficiency and precision.
GPS (Global Positioning System) was developed
in the USA and is the most well-known satellitebased positioning system in the world. The new
term GNSS comprises GPS as well as the Russian
GLONASS and European GALILEO systems. The
satellites orbit Earth at an altitude of approximately
20,000 km (12,000 miles) and keep transmitting
positioning signals towards Earth. These signals
enable suitable receivers on Earth to calculate their
position with pinpoint accuracy. Access to the
satellite data is free.
A signal broadcast by the GPS / GNSS satellites
includes the following information: type of satellite,
position, and time the message was sent. To calculate its own position, the GPS receiver compares the time the message was sent with the time
it was received. The time difference enables the
receiver to compute the distance to the satellite.
As many as 48 GPS / GNSS satellites currently
orbit Earth in a precisely defined pattern which
enables the signals of at least four satellites to be
received at any given time. These signals permit
determination of the receiver’s current position.
There is the risk of not being able to receive the
signals of a sufficient number of satellites when in
the vicinity of houses or ground elevations. If this
is the case, the receiver needs to be positioned
in a different location where it can “see” a larger
number of satellites.
The digital terrain model is prepared by a surveyor
who carries out measurements at different points
of the terrain in question. The current position of
the measuring system used can then be transferred to the digital model via fixed points.
= digital stringline
Horizontal position of a road in the digital terrain model
166 // 167
10.3.3
Even today, the use of satellite systems permits
positions to be calculated within an accuracy
range of 2 cm to 3 cm (0.8” to 1.2”) only.
A rotating laser or total station is therefore used as
an additional reference, supplying position details
for the paving level. Combining satellite-based
measurements with laser-based measurements
or a total station delivers the accuracy in the
millimeter range that is required in modern road
construction.
Total stations are electronic angle and distance
measuring systems (tachymeters). A transmitter
sends a laser beam to a bearing point (prism) at
the machine from where it is reflected back to
the transmitter. This system enables the precise
measurement not only of horizontal distances but
also of differences in level, horizontal angles or
vertical angles.
Expert’s tip:
• Both the operation of the 3D system and
the quality of the finished product are determined by the quality of the digital terrain
model. The model therefore needs to be
prepared with utmost care!
• The 3D system greatly influences logistics
on the construction site.
Good organization of the paving process
can significantly increase the overall economic efficiency.
The total station accurately determines the
position of a prism across a distance of 100 m
to 150 m. As it is motorized, the total station is
capable of tracking the prism automatically.
At an advance speed of the slipform paver
of approx. 2 meters per minute, the total
station needs to be repositioned every 90 to
120 minutes. The use of several total stations
therefore offers the advantage of being able
to complete paving more quickly and without
any breaks in the paving operation.
Four-track control using two automatic total stations
168 // 169
10.3.4
Functionality
One or two prisms are installed on the slipform
paver, each of which has direct visual contact to
a total station, reflecting their laser beam.
The total station keeps determining the prism’s
current position. The measured results are transmitted by radio to the system computer on the
paver. Two multi-axial slope sensors integrated in
the machine additionally determine the paver’s
longitudinal and cross slope. The system computer
uses these parameters to calculate the machine’s
actual position and direction of travel. The position
data are continuously compared with the design
Check
measurement
Digital model
Actual position
Flow of data in a 3D control system
data of the concrete profile stored in the system
computer as a digital model. Any deviations are
immediately forwarded by the system computer to
the paver’s machine control system.
The paver’s control system then initiates the
required corrections in level, slope and steering
angle of the crawler tracks. This procedure enables the production of concrete profiles that meet
the specified requirements with great accuracy.
Processing the data in the system computer
additionally produces a full documentation of
the paving operation.
3D
interface
PLC
10.3.5
Benefits
Paving concrete without the use of stringlines
offers great economy of time. Establishing the
required geodetic data is much more cost-effective
than the time-consuming and labor-intensive work
of surveying and installing the stringlines.
Removing the stringlines again after completion
of the paving operation is also not required. In
addition, the digital model prepared once can be
used by all machines involved in the construction
project, which not only leads to increased accuracy in the production of all layers to be built, but
also helps to save expensive materials.
Work is made easier also for the drivers of transport trucks and concrete mixer trucks, as they will
not have to watch out for tensioned stringlines and
can drive up to the paver straight away.
nates the hazard of tripping over the stringlines.
Touching the stringlines may alter their surveyed
position, leading to an incorrect horizontal position
of the paved concrete profile or slab. This is critical
in particular because any damage to the stringlines
or an alteration of their position is not necessarily
visible to the naked eye but can result in severe
paving errors. Problems due to space limitations
(for instance, in tunnel construction) are obviated.
Human error is also minimized: the paver operator
can fully focus on the paving operation and
feeding of the paver with concrete mix, and will
not have to intervene manually into the paver’s
automatic steering function.
The stringless system also provides increased
safety for the crew working on site as it elimi-
170 // 171
11 Parameters influencing the
paving process
11.1
Concrete mix
176
11.2
Paving parameters
178
11.3
Machine settings
179
11.4
Interaction of machine weight and concrete buoyancy
180
172 // 173
Maximum efficiency and outstanding work results
can only be achieved with detailed knowledge of
as many of the factors as possible that influence
the concrete paving process.
quality of the concrete profile. It is therefore vital
to adhere to the recommendations on the various
parameters given in the section below.
Neglecting even one of these parameters can result in a significantly inferior or even unacceptable
174 // 175
11.1 Concrete mix
he concrete composition needs to be manufacT
tured in accordance with the standard specified
in the tender specification.
ll source materials need to be added with a
A
tolerance not exceeding 3%.
he constituents of the concrete mix need to be
T
added in accordance with a mixing instruction
(standard).
oncrete consistency needs to be checked
C
regularly during operation on the construction
site; consult staff of concrete mixing plant if
required.
onsistent composition of the concrete mix
C
needs to be ensured for the duration of the
entire production process.
he maximum aggregate size should not exceed
T
one third of the smallest thickness of the concrete slab or profile to be built.
he coarser the aggregate selected, the less
T
workable the resulting concrete mix will be.
sing round in lieu of crushed aggregate will
U
improve the workability of the concrete mix.
ound aggregate, which improves the worka
R
bility of the concrete mix, is suitable for the
production of curb and gutter profiles.
rushed aggregate, which reduces the workaC
bility of the concrete mix, is suitable for higher
concrete profiles as it offers increased stability.
etailed knowledge of the aggregate’s surface
D
moisture is of vital importance as it has an
influence on both material quantity and concrete
consistency.
Concrete quantity
he concrete quantity needs to be adjusted to
T
actual requirements.
he supply of concrete per unit of time needs to
T
match the speed of the paving operation.
Reinforcement
ake sure that a sufficient quantity of reinforceM
ment (minimum = daily production rate) is stored
on the construction site – breaks in the paving
operation should be avoided.
Concrete transport
aximum permissible transport times need to
M
be adhered to in accordance with prevailing
ambient temperatures.
hen dump trucks are used for transport, the
W
dumping bodies must not be made of aluminium, as even low amounts of aluminium abrasion
will lead to gas development in the cement
paste.
sufficient number of transport vehicles needs
A
to be provided for concrete delivery.
ccess routes for site vehicles need to be
A
provided and clearly identified as such.
Continuous supply of concrete is a prerequisite for the economical paving of concrete profiles
176 // 177
11.2 Paving parameters
Cross-section of the concrete profile
he cross-section of the concrete profile to be
T
built has an influence on the ideal paving speed.
Vibrators
Vibrator frequency ranges from 0 to 200 Hz.
he frequency of the individual vibrators
T
installed in different positions can be varied
as and when required.
n ideal degree of compaction has been
A
achieved when the concrete has stopped
settling and shows an even and closed surface
with only occasional air bubbles.
Mold inclination
he mold is inclined during paving to counteract
T
any settling effects occurring during concrete
compaction.
he higher a concrete profile is produced relative
T
to its width, the larger the angle of incline of the
mold needs to be.
In some instances, angles of incline have already
been incorporated in the shape of the mold.
Weather influences
xternal factors like ambient temperatures can
E
have an influence on the concrete quality. Ideal
paving temperatures range from 5°C to 30°C
(40°F to 85°F).
11.3 Machine settings
Feeding
oncrete feeding needs to be organized so
C
that there will always be a sufficient amount of
concrete in the mold.
minimum amount of concrete needs to be
A
provided in the hopper at all times in order to
ensure constant pressure in the mold and
complete filling of the mold.
ontinuous delivery of concrete from the conC
crete mixer truck is not always ensured during
offset paving applications in tight radii.
The auger conveyor is better suited than the belt
conveyor in such a case as it can often be filled
with a sufficient amount of concrete to ensure
continuous paving.
Number and position of vibrators
If the number of vibrators used is too small,
insufficient and non-uniform vibration will result,
leading to insufficient compaction and cracking.
he vibrators need to be positioned so as to
T
ensure de-aeration of the concrete right at the
inlet of the mold’s profiling section.
he vibrators including suspension need to be
T
arranged so that a continuous flow of concrete
is guaranteed.
Stringline
irection and height of the stringline need to
D
be checked at regular intervals for each con
struction section to prevent paving errors.
he stringline should preferably be positioned
T
as close to the concrete profile as possible.
he number of vibrators used depends on both
T
the concrete consistency and the geometry and
size of the concrete profile to be built.
If too many vibrators are used, excessive
vibration will result, causing the so-called
“orange peel” effect as well as swelling of the
concrete behind the mold.
Further effects that may occur are aggregate
segregation and related loss of strength.
178 // 179
11.4 Interaction of machine weight and
concrete buoyancy
G = machine weight
F = concrete buoyancy
If the slipform paver’s own weight is too low, it will
be lifted up by the effect of concrete buoyancy,
which in turn will lead to a defective paving result.
The machine weight, which counteracts the uplifting process, is therefore a crucial performance
criterion.
The following applies to all types of applications:
Buoyancy depends on concrete consistency and
is very difficult to determine by way of calculation.
• Slipform pavers usually have a sufﬁciently
high own weight to safely counteract any
buoyancy forces. It is recommended nevertheless to mount the mold as close to the
chassis as possible and to fill the water tanks
to full capacity for improved traction!
G >> F
Expert’s tip:
180 // 181
12 Paving errors and error correction
12.1
Illustrated examples and recommended corrective action186
182 // 183
Paving concrete to professional standards is a
highly complex process. Extensive experience and
expertise are required in particular for determining
the correct mixing ratio and for effective vibration
of the concrete mix. Incorrect paving of concrete
can incur tremendous repair costs – and may
even require complete demolition of the freshly
produced concrete profile. It is of vital importance,
therefore, to recognize any errors as early as
possible and to take appropriate corrective action.
184 // 185
12.1Illustrated examples and recommended
corrective action
Error / Cause
Cracks in the concrete profile caused by
excessively dry concrete
Corrective action
Increase
the w / c ratio (water-cement proportion)
of the concrete mix within the permissible range
Correct the mold’s angle of incline if required
Error / Cause
Swelling of the concrete profile caused by ex
cessively fluid concrete, or an “orange peel”
effect on parts of the profile surface
Corrective action
educe the w/c ratio (water-cement proportion)
R
of the concrete mix
Correct the vibrator frequency if required
Error / Cause
Irregular horizontal or vertical course of the
concrete profile caused by incorrect stringline
parameters
Corrective action
Check positioning of the stringline
Error / Cause
Leaking of considerable amounts of concrete at
the side of the mold caused by an uneven base,
and related loss of head pressure in the mold
Corrective action
repare or level the base (e.g. with
P
a trimmer)
Use hydraulic sideplates
186 // 187
corrective action
Error / Cause
Excessively dry concrete is partly dragged along
by the slipform paver’s advance movement,
resulting in damages ranging from minor cracks to
major disruptions
Corrective action
Increase the w/c ratio (water-cement proportion)
Error / Cause
Excessive or insufficient layer thickness of the
completed profile caused by inadequate pre
paration of the base, possibly resulting in
deformation or even tearing of the sliding plate
Corrective action
he base or excavated trench needs to be
T
carefully tailored to the specified shape of the
concrete profile to be built
Error / Cause
Insufficient cohesion of the paved material caused
by excessively moist concrete
Corrective action
educe the w / c ratio (water-cement proportion)
R
Reduce vibrator frequency if required
Error / Cause
Irregular surface of the concrete profile
Corrective action
Increase the mold’s angle of incline if required
heck that there is a sufficient amount of
C
concrete in the hopper
188 // 189
corrective action
Error / Cause
Gaps of material in the paving profile caused by insufficient contact pressure in the compaction zone
Corrective action
heck that there is a sufficient amount of
C
concrete in the hopper
Error / Cause
umps in the concrete profile following a break in
B
the paving operation
Corrective action
Run vibrators only after traveling forward
Try to avoid machine stoppages
Error / Cause
“Orange peel” effect on the profile surface
Corrective action
Correct vibrator frequency
Readjust vibrator positions
educe the w / c ratio (water-cement proportion)
R
of the concrete mix
Error / Cause
Significant cracking in the profile caused by
excessively dry concrete
Corrective action
Increase slump proportion of the concrete mix
Reduce the mold’s angle of incline if required
Increase vibrator frequency initially after pauses
educe machine downtime during breaks in
R
operation
190 // 191
corrective action
Error / Cause
“Pitted” surface texture; air cannot escape from
the concrete as quickly as necessary
Corrective action
Correct the mold’s angle of incline if required
Clean de-aeration slot, if applicable
Error / Cause
Swelling of concrete leads to an increase in
volume or the formation of bumps
Corrective action
Reduce vibrator frequency
192 // 193
13 Basics of design
13.1
Concrete requirements 198
13.1.1 Concrete requirements for offset paving 198
13.1.2
Concrete requirements for slab paving 199
200
13.2.1 Paving capacity in offset paving
200
13.2.2
201
202
13.3.1 Conveying capacity of auger conveyor
202
13.3.2
204
194 // 195
The successful construction of concrete structures
calls for the material requirements to be calculated
in advance. In addition, the paving capacity of the
slipform paver needs to be calculated to deter-
mine the delivery cycles or supply of materials by
transport vehicles. This procedure will enable the
slipform paver to place the concrete in a contin
uous operation.
196 // 197
13.1 Concrete requirements
13.1.1
Concrete requirements for offset paving
A
L
Parameters for calculating concrete requirements
A = cross-sectional area of profile [m2]
L = paving length [m]
V = concrete quantity [m³]
Example:
A = 0.3 m2
L = 1,000 m
V = 0.3 m2 x 1,000 m = 300 m3
V=AxL
13.1.2
Concrete requirements for slab paving
c
a
b
Parameters for calculating concrete requirements
a = paving width [m]
b = paving length [m]
c = paving thickness [m]
V = concrete quantity [m³]
Example:
a=2m
b = 3,500 m
c = 0.2 m
V = 2 m x 3,500 m x 0.2 m = 1,400 m3
V=axbxc
198 // 199
13.2.1
Paving capacity in offset paving
ρ
A
L
Parameters for calculating the paving capacity
A = cross-sectional area of profile [m²]
v = paving speed [m / min]
ρ = specific weight of concrete mix [kg / m³]
Q = paving capacity [m³ / min]
Q=vxA
Example:
v = 2 m / min
A = 0.25 m²
ρ = 2,400 kg / m³
Q = 2 m / min x 0.25 m2 = 0.5 m3 / min
Note: In order to extrapolate to the quantity processed per time unit [kg / min], the paving capacity Q
needs to be multiplied by the concrete density ρ.
13.2.2
c
a
ρ
b
Parameters for calculating the paving capacity
a = paving width [m]
c = paving thickness [m]
v = paving speed [m / min]
ρ = specific weight of concrete mix [kg / m³]
Q = paving capacity [m³ / min]
Q=vxaxc
Example:
v = 2 m / min
a=2m
c = 0.1 m
ρ = 2,400 kg / m³
Q = 2 m / min x 2 m x 0.1 m = 0.4 m3 / min
Note: In order to extrapolate to the quantity processed per time unit [kg / min], the paving capacity Q
needs to be multiplied by the concrete density ρ.
200 // 201
13.3.1
Conveying capacity of auger conveyor
S
n
α
d
Parameters for determining the conveying capacity
A = auger cross-section [m²]
d = auger diameter [m]
s = auger flight [m]
n = auger speed [¹ / min]
α = angle of auger incline [°]
Q = conveying capacity [m³ / min]
Q = A x s x n x 0.3 x (1 – 0.02 x α) =
π x d2 / 4 x s x n x 0.3 x (1 – 0.02 x α)
Example:
d = 0.4 m
s = 0.35 m
n = 80 1 / min
α = 30°
Q=πx
(0.4 m)2
x 0.35 m x 80 1 / min x (1 - 0.02 x 30°) = 1.4 m3 / min
4
Note: The formula is provided for an approximate calculation of the conveying capacity only.
202 // 203
13.3.2
X
v
α
X
X–X
A
B
β = 30°
Cross-section of bulk material (β = 30°)
A=
(0.9 x B - 0.05)2
0.068 dm2
Parameters for determining the conveying capacity
Note: In the quantity equation, B needs to be included as a numerical value in [m]. A is obtained in [dm²].
A = cross-section of bulk material
B = belt width [m]
v = belt speed [m / s]
g = weight of concrete = 2,400 kg / m³ (wet)
α = angle of conveyor incline [°]
k = correction factor depending on angle of incline [ ]
Q = conveying capacity [m³ / min]
Angle of incline α
16°
18°
20°
22°
24°
26°
Correction factor k
0.89
0.85
0.81
0.76
0.71
0.66
Q = 530 x v x (0.9 x B – 0.05)2 x k
60
Example:
v = 2 m / s
B = 0.6 m
α = 22°
530 Q=
x 2 x (0.9 x 0.6 - 0.05)2 x 0.76 = 3.2 m3 / min
60
Note: In the quantity equation, v needs to be included in [m / s], and B needs to be included in [m]. The
result will be the conveying capacity expressed in [m³ / min]. The results may deviate, up or down,
depending on concrete consistency.
204 // 205
14 Concrete science 14.1
210
14.2
Aggregate and grading curve
212
14.3
Concrete properties
217
14.4
Distinguishing characteristics
218
14.5
Production in the concrete plant
219
14.6
Causes of poor concrete quality
220
206 // 207
No two types of concrete are alike – it’s the
right mixture that matters. The wide variety of
mix options enables concrete to be tailored to
different requirements.
208 // 209
14.1 Composition of the concrete mix
The basic formula of concrete is simple: cement
consisting of shale, limestone and gypsum; coarse
and fine aggregate (gravel and sand), and water.
Cement plays the key role: it is mixed with water to
form the cement paste that bonds the aggregate,
thus creating a material that resembles hard rock.
The various types of aggregate constitute the
largest portion in terms of volume.
Cement / Cement-like materials
They form the backbone, and additionally play
an important role in the quality and workability of
the concrete mix. The concrete properties can be
influenced by adding additives, such as fly ash,
and admixtures, such as plasticizers. At normal
temperatures and humidity, concrete has usually
reached a very high percentage of its final strength
after 28 days following the paving operation.
Aggregate
Sand 0 - 2
Portland cement
Gravel 2 - 8
Gravel 8 - 16
Fly ash
Composition of concrete
Gravel 16 - 22
Admixtures
Concrete
Water
Chemical admixtures
210 // 211
14.2 Aggregate and grading curve
It is of vital importance that the aggregate gradation be optimized. Well graded aggregate reduces
the voids that have to be filled with cement.
If a concrete mix is not well graded, larger quantities of expensive cement must be used to achieve
workable results. To be able to produce highquality concrete tailored to a specific application,
it is important to determine the aggregate size
distribution.
~ 32 mm
~ 22 mm
~ 16 mm
~ 8 mm
~ 4 mm
~ 2 mm
212 // 213
The set of test sieves comprises various sieves of different mesh sizes
A sieve test can be performed to determine the
proportions of certain aggregate sizes.
A set of test sieves is required for doing so which
comprises square-hole sieves and wire mesh
sieves as well as a receiver pan. The sieves smaller
than 4 mm are wire mesh sieves, those from 4 mm
to 63 mm are square-hole sieves.
The sieves are placed on top of one another
A test sample is placed in the uppermost sieve.
The set of sieves is shaken mechanically or
manually until the sieving process is complete.
The material left on the different sieves is weighed
one after the other. To do so, the material in the
uppermost sieve is weighed first, and the material
left in each of the next sieves is then added to that
of the previous sieve(s) to be weighed together.
214 // 215
Passing the sieve in % by weight
100
1
= coarse aggregate
90
2
= gap gradation
80
3
= coarse to medium aggregate
4
= medium to fine aggregate
5
= fine aggregate
70
5
60
4
50
3
40
2
30
1
20
10
0
0
0.125
0.25
0.5
1
2
Mesh size in mm
4
8
16
31.5
Grading curve of a typical concrete used for slipform paving
The grading curve is a graphical representation
of the aggregate distribution after separation into
the various size fractions by the different types of
sieves. A favorable grading curve will ensure that
the voids among different size aggregates will be
minimized.
The following basic rules apply:
he maximum aggregate size needs to be seT
lected to ensure workability, and the other sizes
need to fill the voids to the greatest possible
extent.
he fewer the number of voids in the finished
T
concrete, the higher the compressive strength.
Note:
Even though the aggregate added to the concrete
mix is precisely defined in terms of size and quantity by means of the grading curve, its properties
will also depend on its inherent qualities.
Aggregate containing iron may cause patches of
rust, for example, while aggregates with silica or
silicate can react with alkali in cement to induce
severe cracking.
14.3 Concrete properties
The properties of concrete can be specifically
controlled by modifying the mixing proportions –
they are dependent on the cement content, quantity of mixing water, water-cement ratio, gradation,
aggregate quality, chemical additives, ultra-fines
content, type of compaction or curing method.
The wide variety of mixing options enables the
concrete properties to be tailored to most any
requirement. Special properties depending on the
concrete class include: high compressive strength,
water impermeability, high freeze-thaw resistance,
resistance to chemical attack, high resistance to
wear and tear, or suitability to high temperatures
of use.
Poor quality of the fresh concrete mix – the concrete
crumbles into small pieces
The percentages of the various constituents need
to be calculated precisely for the concrete formula
in order to achieve the parameters specified for
the final strength, air content and water-cement
ratio of the concrete structure.
Expert’s tip:
• A characteristic feature of concrete well
suited for slipform paving is that it can be
molded by hand like a snowball, retaining its
shape, and that the surface is only slightly
moist.
Good quality of the fresh concrete mix – a concrete ball,
molded by hand, retains its shape
216 // 217
14.4 Distinguishing characteristics
Concrete can be distinguished in terms of
ensity (lightweight concrete, ordinary concrete,
d
heavy concrete)
compressive strength
lace of production, intended use or state of
p
hardening (site-mixed concrete, ready-mixed
concrete, waterproof concrete, underwater
concrete, fresh concrete, hardened concrete)
onsistency (self-compacting concrete, flowing
c
concrete, stiff concrete)
14.5 Production in the concrete plant
Stationary concrete plant
Concrete is produced in a mixing plant on the
construction site (site-mixed concrete) or in a
stationary mixing plant (ready-mixed concrete).
Ready-mixed concrete is transported to the
construction site by concrete mixer trucks.
When concrete processing and hardening takes
place on the construction site, the concrete used
is called cast-in-situ concrete, as opposed to
precast concrete elements which are prefabricated
and then placed.
following sequence: aggregate, cement and additives first, followed by water and admixtures. Once
the mass has been mixed for the specified time,
the mixer opens, and the concrete flows into the
concrete mixer truck.
In order to not impair the quality of the concrete,
the concrete formula always needs to account
for both transport distance and transport time.
As a general rule, concrete should be fully placed
within 90 minutes.
The different types of aggregate are weighed and
then fed into the mixing plant. Cement, additives
and admixtures are weighed at the same time.
The constituents are fed into the mixer in the
218 // 219
14.6 Causes of poor concrete quality
The most common causes of poor concrete
quality include:
insufficient mixing time
incorrect grading curve
incorrect mixing ratio
incorrect type of aggregate
inferior cement quality
impurities
se of recycled water containing chemical
u
additives
long transport distances
Hardened concrete in transport vehicle, probably caused by either flash set or long transport time
220 // 221
15 Bibliography and image credits
Bibliography
- H. Eifert, A. Vollpracht, O. Hersel: Straßenbau
heute – Betondecken. Hrsg.: Bundesverband der
Deutschen Zementindustrie, Düsseldorf. Verlag Bau
+ Technik 2004, 5. Auflage. (Road construction
today – concrete pavements. Published by: Federal
Association of the German Cement Industry,
Düsseldorf.)
- D. Schubenz, J. Scheiblauer: Straßenbau heute –
Heft 2, Tragschichten mit hydraulischen Bindemitteln. Hrsg.: Bundesverband der Deutschen
Zementindustrie, Köln. Beton-Verlag GmbH 1990,
2. Auflage. (Road construction today – Vol. 2, base
courses with hydraulic binding agents. Published
by: Federal Association of the German Cement
Industry, Cologne.)
- R. Weber: Guter Beton – Ratschläge für die richtige
Bauberatung. Hrsg.: Bundesverband der
Deutschen Zementindustrie, Köln. Beton-Verlag
GmbH 2007, 22. Auflage. (Good concrete – recommendations on the right building consultancy.
Published by: Federal Association of the German
Cement Industry, Cologne).
Concrete Construction Methods: ZTV Beton-StB
07 – Additional technical contract conditions and
guidelines on the construction of base layers with
hydraulic binding agents and road pavements from
concrete. Published by: Road and Transportation
Research Association, Cologne.)
- K. Wesche: Baustoffe für tragende Bauteile – Band
1, Grundlagen. Bauverlag GmbH, Wiesbaden und
Berlin 1996, 3. Auflage. (Construction materials for
load-bearing structures – Vol. 1, Basics.)
- P. Grübl, H. Weigler, S. Karl: Beton - Arten, Herstellung, Eigenschaften. Hrsg.: H. Kupfer. Ernst &
Sohn Verlag 2001, 2. Auflage. (Concrete – types,
production, properties. Published by: H. Kupfer.)
Image credits
The images shown on pages 130, 131, 132, 133,
134 and 135 are the property of Heidelberg-Cement
AG / Entwicklung und Anwendung.
- Arbeitsgruppe Betonbauweisen: ZTV Beton-StB
07 – Zusätzliche Technische Vertragsbedingungen
und Richtlinien für den Bau von Tragschichten mit
hydraulischen Bindemitteln und Fahrbahndecken
aus Beton. Hrsg.: Forschungsgesellschaft für
Straßen- und Verkehrswesen e.V., Köln. FGSV
Verlag GmbH 2007, 5. Auflage. (Working Group on
Illustrations are without obligation. Technical details are subject to change without notice. Performance data depend on operating conditions.
Reproduction, in whole or in part, is not permitted. Copyright and all other rights reserved by Wirtgen GmbH.
Translation, storage, duplication and distribution, including copying on electronic data storage devices, such CD-ROM, video disc, etc., as well as
storage in electronic media, such as screen text, Internet, etc., is not permitted without the prior written consent of Wirtgen GmbH. Any liability for
personal injury, material and financial losses is excluded.
First Edition 2009
Copyright by Wirtgen GmbH
222 // 223
Wirtgen GmbH
Reinhard-Wirtgen-Strasse 2 · 53578 Windhagen · Germany
Phone: +49 (0) 26 45 / 131-0 · Fax: +49 (0) 26 45 / 131-242
Internet: www.wirtgen.com · E-Mail: [email protected]
Illustrations are without obligation. Technical details are subject to change without notice.
Performance data depend on operating conditions. No. 60-50 EN - 11 / 09 © by Wirtgen GmbH 2009 Printed in Germany

Curb, barrier, sidewalk and multipurpose apllications

Transcription

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