Benefits of using GGBS cement in large concrete pours

Greener and stronger foundationsas a result of using GGBS cement

David O’Flynn doflynn@ecocem.ie 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 doflynn@ecocem.ie 087 9654891