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This presentation explains the benefits of using GGBS cement in reducing the risk of thermal cracking, particularly in relation to wind turbine foundations
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Greener and stronger foundationsas 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 establishedEarly 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 UK2006: 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 productionTypical CO2 Emissions for Portland Cement and GGBS Production(Fi i k f )(Figures in kg per tonne of output)
700
800
900
Other energy used
F il F l Upu
t
400
500
600 Fossil Fuel Use
Process Emissions
nn
e o
f O
utp
100
200
300
kg
pe
r T
on
0
100
Portland Cement GGBS
Environmental Savings
Environmental savings per typical base
EquivalentCO2 79.4 tonnes 25 Cars or 10 acres of
mature forestry/yearSO 245 kgSO2 245 kgNOx 343 kgCO 245 kgPM10 42.7 kgE k h P 8 h f Energy 94,000 kwh Power 18 homes for
one yearLimestone/Shale
160 tonnes
www ecocem iewww.ecocem.ie
GGBS – Controlling thermalGGBS – Controlling thermal cracking
Controlling thermal cracking
Image courtesy of Wind Farm Civils
Controlling thermal cracking
Controlling thermal cracking20m x 20m x 2.4 m deep base
Heat of Hydration
GGBS lowers peak and overall heat
Substitution level 70%
Controlling thermal crackingMaximum temperature differential on 1500mm deep base
0% GGBS 30% GGBS26 degrees 25 degrees
50% GGBS23 degrees
70% GGBS19 degrees
Controlling thermal cracking20m x 20m x 2.4 m deep base with 70% GGBS60
50
30
40
Highest
Lowest
20
Lowest
Difference
0
10
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 windCover with plastic sheeting to protect from wind
Remove insulation in stages
GGBS – strength benefits
Long term strength development
85
95
65
75
mm
2 42.5 & 50% GGBS
35
45
55
N/m
42.5
15
25
35 42.5
0 20 40 60 80 100 120 140 160 180 200
Days
Temperature matched curing1.1m deep base with 70% GGBS
4550
Foundation Slab: C40/50 @ 70% GGBS
25303540
h N/m
m2
10152025
Strength
05
1 2 3 4
St d d TMCDay Age
Standard 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
EnvironmentalPositive PR• 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
