the benefits of ggbs cement in concrete 2011 engineers & architects

SustainableSustainableSustainable Sustainable DurableDurableArchitecturalArchitecturalEcocem Green Cement

Learning Outcomes

The learning outcomes from the presentation are:g p

Understand what GGBS cement is

Understand the environmental technical and architectural reasons whyUnderstand the environmental, technical and architectural reasons why you would specify GGBS cement

Know how to specify GGBS cement

Know the % of GGBS cement to specify for different results/applications

Understand the impact of specifying different % of GGBS cementUnderstand the impact of specifying different % of GGBS cement

History of GGBS

1862: Hydraulic potential of GGBS discovered in GermanyGGBS discovered in Germany

Early 1900’s - Portland Blast Furnace Cements had an established place in the concrete market

2004: More than 5,000,0002004: More than 5,000,000 tonnes of GGBS produced in Germany

2006: Approximately2006: Approximately 2,000,000 tonnes of GGBS produced in UK

2008: Over 400,000 tonnes available in Ireland

About Ecocem Ireland

Long term agreement with partner companies f l i hi hfor supplying high quality GBS

Can supply the Irish pp ymarket with over350,000 tonnes from Dublin

Provide technical back up to specifiers and concrete manufactures

GGBS Manufacture

Steel Manufacture Water to make GBS

GBSGrind to make GGBS

Store GGBS for distribution

GGBS Manufacture

GGBS cement, and OPC

Ecocem Cement in Use

NRA OPW B d Gái ESB C ill RPA B d N M L l A h i iNRA, OPW, Bord Gáis, ESB, Coillte, RPA, Bord Na Mona, Local Authorities

Engineers, Architects, Developers, Precast, House builders, Farmers

EnvironmentalEnvironmentalffAdvantages of using GGBSAdvantages of using GGBS

GGBS and the Environment

CO2 emissions for Ecocem GGBS and cement production

Typical CO2 Emissions for Portland Cement and Ecocem GGBS Productionyp 2(Figures in kg per tonne of output)

1000

600

700

800

900

Other Energy Used

Fossil Fuel Use

pu

t

300

400

500

600Process Emissions

Ton

ne

of O

utp

0

100

200

CEM I CEM II/A GGBS ( ith t ff t )

kg p

er

CEM I CEM II/A GGBS (without offsets)




1000

600

700

800

900

Other Energy Used

Fossil Fuel Use

pu

t

300

400

500


Ton

ne

of O

utp

0

100

200

CEM I CEM II/A E GGBS ( ith t

kg p

er

CEM I CEM II/A Ecocem GGBS (without offsets)




1000

600

700

800

900

Other Energy Used

Fossil Fuel Use

pu

t

300

400

500


Ton

ne

of O

utp

0

100

200

CEM I CEM II/A E GGBS ( ith

kg p

er

CEM I CEM II/A Ecocem GGBS (with offsets)


Depletion of naturalDepletion of natural resources

For every tonne of Portland cement produced, 1.6 tonnes of limestone/shale are removed from the landscape

GGBS production involves no quarrying of limestone or clay

GGBS and the EnvironmentE i l

What is the impact of

Environmental savings example

replacing 50% of cement with GGBS in an average size shopping centre, using 5 000m3 of concrete?5,000m of concrete?

See calculator on: www.ecocem.ie

Case Study: Case Study: 33--bed bed semi detachedsemi detachedsemi detached semi detached househouse

Reduction in Embodied CO2 through the use of GGBS

3 bed Semi Detached House3 bed Semi Detached House

OriginalOriginal Embodied CO2(38.7 tonnes)

Reduced E b di d COEmbodied CO2(28.4 tonnes)

Larger embodied CO2 reductions are possible with increased replacement

ref: “Embodied CO2 of housing construction in Ireland” - Architecture Ireland – Jan/Feb 2010

Larger embodied CO2 reductions are possible with increased replacement rates of GGBS


Longer service life from GGBS concreteTime to replacement extendedTime to replacement extended

Specified by NRA on road bridges and structural concrete - 120 year design life achieved

Reduced demand on natural resources for new concrete

Exposure to chloride attack:

Lighter colour - The Albedo Benefit

Solar radiation i fl t d b This heat cannotis reflected by lighter coloured surfaces

This heat cannot pass out of the earth’s atmosphere through the greenhouse gas layer

Darker coloured surfaces absorb solar radiation

Every 100m2 of GGBS concrete pavement in

Ireland will offsetand re emit it as heat

Ireland will offset 6 tonnes of CO2/annum

Lighter colour - The Heat Island Benefit

Reduce heat island effect

Reduces air conditioning requirement; cost and environmental benefit studies have shown reductions of more than 20% inbenefit – studies have shown reductions of more than 20% in building cooling costs whose albedo has been increased (in the US potential saving of $1 billion per year)

Health benefit

Lighter colour – Reflectance Benefit

Reduces outdoor lighting requirements by enhancing night time visibility

Saving money, energy and carbon emissions

Approx. 30% less lighting needed to achieve sameApprox. 30% less lighting needed to achieve same visibility for concrete as it does for asphalt

Properties &Properties &Properties &Properties &Advantages of using GGBSAdvantages of using GGBS

GGBS Chemical Composition

Same constituents as OPC

Different proportions• Less CaO• More Si02

• More Al2O3

Mix design using GGBS cement

GGBS cement replaces ordinary Portland cement on a one-for-one basisone for one basis

No change in any other element of the mix design: • sand• sand• aggregates• w/c ratio (can be reduced)• Admixtures

Concrete manufacture• Batch duration is the same• Time to transport - may be appropriate to extend it

GGBS in Concrete

Engineering benefits start at 30%

Usage varies from 30 up to 85%

Most often specified at 50%Most often specified at 50%• Treated same as Portland cement concrete

No adjustment striking timesPlacing, compacting and powerfloatingConcrete admixtures compatible.

Working with GGBS Concrete

Placing, compacting and pumping easier:eas e• lower relative density• smaller particle sizes

Powerfloating as normal

Setting times longer by 0.5 – 2 hrs g g y

Slower rate of bleeding

W t d d 3% t 5% lWater demand 3% to 5% lower

Compatible with admixtures

Strength – cement prisms

80.0

60.0

70.0

40.0

50.0

mm

2

20 0

30.0

N/m

0 0

10.0

20.0

Days0.0

7 28 90

100/0 Sept 50/50 Sept 30/70 Sept100%OPC/0%GGBS 50%OPC/50%GGBS 30%OPC/70%GGBS

Strength – early age development

on a 350mm

Strength – temperature effects

1.1 metres in depth

40

45

50Foundation Slab: C40/50 @ 70% GGBS

25

30

35

40

h N

/mm

2

10

15

20

Stre

ngt

h

0

5

1 2 3 4

Standard TMCDay Age

Standard TMC

Strength – long term development

95

75

85

95

45

55

65

N/m

m2

42.5 & 50% GGBS

25

35

45

42.5

150 50 100 150 200

Days

Strength – long term development

45

C30/37 concrete, Greystones Marina 50% GGBS: 50% CEM II

Core Strength vs time

40

Core Strength vs time

35

engt

hM

pa

30

Stre

25

1 month 6 Months 12 months 18 Months1 month 6 Months 12 months 18 Months

Durability of GGBS Concrete - Chlorides

Chloride Penetration

L hl id i diff i itLower chloride ion diffusivity

Lower porosity/permeability

Applications: roads and bridges, car parks, sea defences, marine structures.


Effect of GGBS on chloride diffusion in concrete

14

16

/s

CEM II/A-L 320 kg/m3

CEM II/A-V 320 kg/m3

8

10

12

icie

nt

10-1

2m

2/

CEM II/A-L 400 kg/m3

CEM II/A-V 400 kg/m3

4

6

8

iffu

sio

n c

oe

ffi

0

2

0% GGBS 50% GGBS 70% GGBS

Di

0% GGBS 50% GGBS 70% GGBS


BS 6349 – Maritime Structures – Table 22

Durability of GGBS Concrete - Sulphates

Sulphate Resistance

Sulphates react with C3A and Ca(OH)2 to formSulphates react with C3A and Ca(OH)2 to form ettringite

Sulphate Resisting cement (SRPC) has reduced C3A, but no reduced Ca(OH)2, and no reduced porosityporosity

SRPC cannot be used in marine environments

GGBS much lower price than SRPC

Note: In BS8500 the only option recommended as suitable for the most severe

l h (Cl Csulphate exposure (Class DC-4m) is concrete containing at least 66% GGBS

Use of Sulphate resistantUse of Sulphate resistant cement is not permitted


Aggressors:

S l h tSulphatesSodium Sulphate Na2SO4Magnesium Sulphate MgSO4

AcidsAcidsSulphuric Acid H2SO4

0.5Durability of GGBS Concrete - SulphatesMasters Study in UCD, Dublin

0.4

0.45

UCD, Dublin

0.3

0.35

sio

n

0.2

0.25

Ex

pa

ns

CEM I

CEMII

SRPC

CEM I + 70% GGBS

0 1

0.15

%

CEM II + 50% GGBS

CEM II + 70% GGBS

0.05

0.1

0

Days Exposure

Durability of GGBS Concrete - SulphatesBRE Digest 1

Sulphate resistance

Durability of GGBS Concrete

0% GGBS0% GGBS

30% GGBS

50% GGBS

Heat of Hydration

GGBS lowers peak and overall heat

Reduces thermal stressingReduces thermal stressing

Reduces micro-cracking (particularly useful in water retaining structures, basements, podium slab, bridges, stadiums, secant pile walls etc )pile walls etc.)

Optimum substitution level 60 – 85%

Heat of Hydration - wind farm bases

Images courtesy of Wind Farm Civils

Heat of hydration - controlling thermal cracking

temperature differential – 1 metre deep slab summer Basement slab with 70% GGBS

45

50

Min Max Difference

25

30

35

40

10

15

20

25

0

5

08:15 13:00 17:30 08:15 13:00 17:30 08:15 13:00 17:30 08:15 13:00 17:30 08:15 13:00 17:30 08:15 13:00 17:30 08:15 13:00 17:30 08:15 13:00 17:30

06/09/2007 07/09/2007 08/09/2007 09/09/2007 10/09/2007 11/09/2007 12/09/2007 13/09/2007/ / / / / / / / / / / / / / / /


temperature differential – 2.5 metre deep slabBasement slab with 70% GGBS

60.0

70.0 Top

Core

Bottom

Differential Top to Core

Diff ti l B tt t C

40.0

50.0

Differential Bottom to Core

30.0

empe

ratu

re (o C

)

10.0

20.0

Te

0.00 21 28 33 46 58 70 77 92 99 118 139 164 189 234

Time after placing (hours)


Convention Centre, Dublin - basement

Resistance to Fire

Architectural Qualities and Appearance

GGBS is an off-white powderGGBS cement, and OPCLighter, more even-coloured concrete

Smoother, more defect-free ,surface

Suppresses/Eliminates efflorescenceefflorescence

Lower pigment requirements –20% saving

GGBS b d ti lGGBS can be used as partial replacement for white cement, up to 70%


Bridge pier and bridge deckbridge deck, Enfield bypass

Bridge deck 100% OPCBridge deck 100% OPCBridge pier 50% GGBS


Cork Civic Offices - 50% GGBS


Cathleen Falls Bridge – 50% GGBS2006 ICS, Design and Construction Awards


Sleeping Giant – 70% GGBS2007 ICS, Design and C t ti A dConstruction Award


2008 ICS

Sean O’Casey Building Dublin – 50% GGBS

2008 ICS, Design and Construction

Award


Aviva StadiumStadium Dublin

40-70% GGBS


Father Collins Park, Dublin70% GGBS


Charlestown Retail Centre – 45% GGBS


2009 ICS Design and

Cable Stay Bridge, Waterford – 50% GGBS

2009 ICS, Design and Construction Awards


Mizen Head Bridge – 50% GGBS- replacing first RC bridge constructed in Ireland in 1909

Image courtesy of RPS

Ecocem in Concrete = Low Carbon Concrete

Carbon Neutral Concrete

The world’s first Carbon Neutral Building Material launched in 2007 in partnership with the biggest

i th I i h C t ti I d tnames in the Irish Construction Industry:

Treasury Holdings

Pierse

Durkan Group

McNamara

JJ RhatiganJJ Rhatigan

Details on all prestigious projects can be found on

www carbonneutralconcrete iewww.carbonneutralconcrete.ie

How to specify GGBS

COARSE & FINE AGGREGATES Coarse and fine aggregates shall comply with I.S. EN 12620.

CHLORIDE CONTENT The total chloride content of the concrete mix for reinforced concrete shall not exceed 0.4% expressed as a percentage of chloride ion by weight of cement.

CEMENT Normal Portland cement (CEM I, CEM II/A) shall comply with the requirements of IS EN 197 1 The cement shall be delivered to site in standard bags or in bulk containers and shallEN 197-1. The cement shall be delivered to site in standard bags or in bulk containers and shall be stored under dry conditions.

CEMENT ADDITIONS Ground Granulated Blastfurnace Slag (GGBS) is permitted in I.S. EN 206-1 to be used as a Type II addition to CEM I or CEM II/A cements in concrete. Where GGBS is added it replaces the CEM I or CEM II/A cement on a one-for-one basis; the total cementitous material content of the concrete mix does not change, and the GGBS counts fully towards the total cement content and water/cement ratio in concrete. GGBS shall comply I.S. EN 15167-1 and be ground to a blaine of > 4000 cm2/g.

A cement combination comprising 50% GGBS and 50% CEM I or CEM II/A is to be used in all concrete throughout the Project, unless otherwise specified on the drawings or by the Engineer.

Multiple Benefits

Best durability (longer life)• Factor of safety• Reduce lifetime maintenance cost

Best sustainable materialBest sustainable material• Reduces CO2 emissions• Demonstrates commitment to a sustainable agenda

P iti CSR• Positive CSR

Best Architectural• Whiter brighter concrete• Whiter, brighter concrete

Best value for money

Thank You

Thank you for your attentiony y

Should you have any questions in the future:y y q

David O’Flynn; 087 965 4891d fl [email protected]

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