as a result of using GGBS cement

Greener and stronger foundations
as a result of using GGBS cement
David O’Flynn [email protected] 087 9654891
Ecocem Ireland
Brief History of GGBS
1862: Hydraulic potential of GGBS discovered in Germany
Early 1900’s - Portland Blast Furnace Cements had an established
place in the concrete market
2004: More than 5,000,000 tonnes of GGBS produced in Germany
2006: Approximately 2,000,000 tonnes of GGBS produced in UK
2008: Over 400,000 tonnes available in Ireland
GGBS Manufacture
GGBS - Environment
GGBS - Environment
CO2 emissions for GGBS and cement production
Typical CO2 Emissions for Portland Cement and GGBS Production
(Figures in kg per tonne of output)
900
kg per Tonne of Output
800
Other energy used
700
Fossil Fuel Use
600
Process Emissions
500
400
300
200
100
0
Portland Cement
GGBS
Environmental Savings
Environmental savings per typical base
Equivalent
25 Cars or 10 acres of
mature forestry/year
CO2
79.4 tonnes
SO2
NOx
CO
PM10
Energy
245 kg
343 kg
245 kg
42.7 kg
94,000 kwh Power 18 homes for
one year
160 tonnes
Limestone/
Shale
www.ecocem.ie
GGBS – Controlling thermal
cracking
Controlling thermal cracking
Image courtesy of Wind Farm Civils
Controlling thermal cracking
Heat of Hydration
GGBS lowers peak and overall heat
Substitution level 70%
Controlling thermal cracking
Maximum temperature differential on 1500mm deep base
0% GGBS
26 degrees
50% GGBS
23 degrees
30% GGBS
25 degrees
70% GGBS
19 degrees
Controlling thermal cracking
20m x 20m x 2.4 m deep base with 70% GGBS
60
50
40
30
Highest
Lowest
Difference
20
10
0
Controlling thermal cracking
Image courtesy of Wind Farm Civils
Controlling thermal cracking
Maximise use of GGBS to reduce heat generated
Install and monitor thermocouples
Insulate if required
Minimise placing temperature
Cover with plastic sheeting to protect from wind
Remove insulation in stages
GGBS – strength benefits
Long term strength development
95
85
75
N/mm2
65
42.5 & 50% GGBS
55
45
42.5
35
25
15
0
20
40
60
80
100
Days
120
140
160
180
200
Temperature matched curing
Strength N/mm2
1.1m deep base with 70% GGBS
Foundation Slab: C40/50 @ 70% GGBS
50
45
40
35
30
25
20
15
10
5
0
1
2
Day Age
Standard
3
4
TMC
GGBS – Durability benefits
Durability – increased resistance to acids
Peaty soils – acidic environment
0% GGBS
30% GGBS
50% GGBS
Durability – increased resistance to sulphates
Durability – increased resistance to salts
Marine Environment
Lower chloride ion diffusivity
Lower porosity/permeability
Durability – increased resistance to salts
BS 6349 – Maritime Structures – Table 22
Summary
Environmental
• Positive PR
• Assist with planning applications
• Consistent ethos
Reduced risk of cracking
• Longer life
• Reduced maintenance
Increased long term strength
Improved durability
• Increased resistance to attack in peaty/acidic environments
• Increased resistance to attack in marine environments
David O’Flynn [email protected] 087 9654891