Cement in Sustainable Construction - Specification...

CEMENT

Cement in

SustainableConstruction

TM

CI/SfB

November 2011

Yq2

CEMENT IN SUSTAINABLE CONSTRUCTION

PAGE 2 I CEMENT IN SUSTAINABLE CONSTRUCTION

The CEM CategoriesFactory-produced cements to BS EN 197-1 are given thedesignation CEM.

A CEM I cement is a traditional Portland cement.

Cements designated CEM II, CEM III, CEM IV and CEM V arefactory-made composite cements - see Table 1. These compositecements blend the clinker used in CEM I cement with othermaterials, often by-products of other industries. Use of thesenon-CEM I cements should become more widespread asspecifiers take account of the sustainability credentials of a cement.

Composite cements also have enhanced performance characteristics compared with CEM I cement - see the Product Selector on page 3.

Introduction

Cement plays a major part in nearly all construction projects. Specifyingcement with a smaller carbon footprinthelps to make construction moresustainable. The Cement SustainabilityInitiative, to which Lafarge Cement UKis a signatory, demonstrates the UKcement industry’s commitment to sound environment performance and responsibility.

Lafarge Reduced Carbon cement used in the construction of the Glendoe Hydro Scheme near Loch Ness – the biggest hydro-electric power station to be built in Scotland for almost 50 years.

LafargeReducedCarboncementsLoweremissionsLowerembodiedenergyMoresustainable

Front coverphotograph: 12 wind farms arebeing supplied withLafarge’s Phoenixcement, includingWhitelee inScotland, which willbecome Europe’sbiggest onshore windfarm. Phoenix is asustainable ReducedCarbon cement thatreduces embodiedCO2 through theaddition of fly ashrecycled from powerindustry waste.

Table 1 – Types of factory-made composite cement included in BS EN 197-1

CEM II

Portland-slag cement (S) Portland-silica fume cement (D) Portland-pozzolana cement (P, Q) Portland-fly ash cement (V, W) Portland-burnt shale cement (T) Portland-limestone cement (L, LL) Portland-composite cement (M)

CEM III

Blastfurnace cement

CEM IV

Pozzolanic cement

CEM V

Composite cement

Saving EnergyLafarge Reduced Carbon cements have a lower embodied energyand an inherently smaller carbon footprint than standard CEM IPortland cements. A characteristic of Reduced Carbon cementsis that less energy is used during their manufacture comparedwith a CEM I cement and so less carbon dioxide is emitted.

Reduced Carbon cements comprise Portland cement and up to65% of other single constituents, such as fly ash, blastfurnaceslag and limestone. The addition of such materials brings thedual benefits of enhanced environmental sustainability and improved performance.

A full list of the Reduced Carbon cements produced by LafargeCement UK is shown on pages 6 and 7 of this publication. To find out about other ways in which we are meeting thechallenge of sustainable development visit www.lafarge.co.uk

CEMENT IN SUSTAINABLE CONSTRUCTION I PAGE 3

Reduced Carbon Cements Product Selector

Key concrete and mortarcharacteristics

General purposeCEM II/A-LL

32,5R

General purposeCEM II/B-V

32,5R

MastercreteCEM II/A-LL

32,5R

SulfacreteCEM II/B-V

32,5R

Embodied CO2/tonne ✔ ✔✔ ✔ ✔✔

Quick setting ✔✔ ✔ ✔✔ ✔

Cohesivenes ✔✔ ✔✔✔ ✔✔ ✔✔

Frost resistance ✔✔ ✔ ✔✔ ✔

Early strength ✔✔ ✔ ✔✔ ✔

Strength gain after 28 days ✔ ✔✔✔ ✔ ✔✔✔

Light colour ✔✔ ✔ ✔✔ ✔

Below ground use ✔ ✔✔ ✔ ✔✔✔

Key concretecharacteristics

Portland-limestoneCEM II/A-LL

42,5N/52,5N

PhoenixCEM II/B-V

42,5N

CemergiCEM III/A

42,5L

Embodied CO2/tonne ✔ ✔✔ ✔✔✔

Pumpability ✔✔ ✔✔✔ ✔✔

Quick setting ✔✔✔ ✔✔ ✔

Low bleed ✔✔ ✔✔✔ ✔

Early strength ✔✔✔ ✔✔ ✔

Strength gain after 28 days ✔ ✔✔✔ ✔✔✔

Resistance to chlorides ✔ ✔✔✔ ✔✔✔

Resistance to sulfates ✔ ✔✔✔ ✔✔✔

Low alkali ✔ ✔✔ ✔✔✔

Low heat of hydration ✔ ✔✔ ✔✔✔

Light colour ✔✔ ✔ ✔✔✔

Satisfactory ✔

Recommended ✔✔

Highly recommended ✔✔✔

Bulk Cements

Packed Cements

Key

A range of LafargeReduced Carboncements is availablefor bulk delivery orpacked in bags. TheProduct Selector onthis page summarisesthe characteristics ofLafarge ReducedCarbon cements inbulk and packed formto enable you to makean informed choice.



Portland-fly ash cement Fly ash is also referred to as fuel ash or pulverised fuel ash(PFA). It is the fine ash produced when coal is burnt at hightemperatures and pressures in coal-fired power stations andfurnaces.

Fly ash is extracted from flue gases by electrostatic precipitators and consists in the main of spherical fine glassy particles with a high silica and alumina content.

Portland-fly ash cement is specified by BS EN 197-1. There are two types of cement, containing between 6% and35% of siliceous fly ash. The designations for factory-madePortland-fly ash cements are:

• CEM II/A-V which contains 6-20% fly ash.

• CEM II/B-V which contains 21-35% fly ash.

Reduced Carbon Cements Promoting SustainabilityDescribed on the right are the characteristics of the three typesof Reduced Carbon cement produced by Lafarge Cement UK.

Lafarge Reduced Carbon cements comprise Portland cementclinker or CEM I cement combined with either:

• Fly ash• Limestone• Blastfurnace slag

By incorporating these materials, Lafarge’s Reduced Carboncements promote environmental benefit and sustainability by reducing landfill or, in the case of limestone, by using a plentiful naturally occurring material. Lafarge’s ReducedCarbon cements reduce the embodied CO2. For a full list ofLafarge’s Reduced Carbon products, please see pages 6 and 7.

Lafarge Phoenix Portland-fly ash cement used at Whitelee wind farm.

Blastfurnace cementGround granulated blastfurnace slag (GGBS) is a by-product of iron production. Iron ore, coke and limestone are fed intothe furnaces and the iron ore is converted into molten ironthat sinks to the bottom. The remaining materials form a slag that floats on top.

The slag is rapidly quenched in water, a process known as granulation, and produces glassy granules similar inappearance to coarse sand. This process changes themineralogy of the slag, making it suitable for use as acementitious material. The slag is then dried and ground to a fineness similar to that of Portland cement. The ground slagis then blended with Portland cement or ground clinker andgypsum to produce the final cement.

Blastfurnace cement is specified by BS EN 197-1.

The designations for factory-made Blastfurnace cements are:

• CEM III/A containing 36-65% slag.

• CEM III/B containing 66-80% slag.

• CEM III/C containing 81-95% slag.

Portland-limestone cementPortland-limestone cements are specified by BS EN 197-1.There are two types containing 6-20% and 21-35% limestone fines respectively. The designations for factory-made Portland-limestone cements are:

• CEM II/A-L (or A-LL) which contains 6-20% limestone.

• CEM II/B-L (or B-LL) which contains 21-35% limestone.

The suffix -LL, signifies a source of high purity limestone witha particularly low content of organic material.

The limestone is generally interground (rather than blended)with Portland cement clinker and the cements are available inall standard strength classes.


Key performance benefits of using Limestoneas a cement enhancer:

• Similar performance to CEM I cement.

• Bleeding is significantly reduced.

• Paler in colour than CEM I.

Key performance benefits of using fly ash as a cement enhancer:

• Increases strength and durability due topozzolanic reaction.

• Improves sulfate resistance and reducesthe risk of alkali-silica reaction.

• Reduces the water required for equalworkability, which in turn improvesimpermeability.

• Reduces the heat of hydration.

• Improves pumpability.

• Increases the surface finish quality.

• Reduces creep and shrinkage.

• Reduces efflorescence in concreteproducts.

• Each tonne of fly ash re-used in cementitiousproducts saves on average 900 kg of CO2emissions. It reduces CO2 emissions by:– Reducing the amount of CEM I (a moreenergy-intensive cement) in the mix.

– Saving energy on excavation, processing and transportation of raw materials.

– Having a lower water demand, which in turnsaves energy.

• Recycles a ‘waste’ by-product of the coal powerindustry that would otherwise go to landfill orash lagoons.

• Owing to its low density, reusing ash saves agreater weight of natural aggregates and reducestransportation impacts.

• By replacing primary aggregates, it conservesvaluable natural resources and habitats.

• Manufacturing process leads to reduced CO2emissions and reduced energy consumption.

• Limestone is a readily available raw materialthroughout the world.

Key performance benefits of using GGBS as a cement enhancer:

• Improved workability.

• Reduced early-age temperature rise.

• Lighter colour.

• Enhanced sulfate resistance.

• Resistance to chloride-related corrosion of reinforcement.

• Resistance to cracking caused by alkali-silica reaction.

• Compatible with admixtures.

[1] This reduction in emissions reflects the impactinvolved in processing granulated blastfurnace slag foruse in cement. It does not take account of the impact ofiron making because the slag is produced irrespective ofwhether or not it can be used.

• Replacing one tonne of CEM I with one tonne ofGGBS reduces CO2 emissions by approximately90%[1}. It reduces CO2 emissions by:

– Reducing the amount of CEM I (a moreenergy-intensive cement) in the mix.

– Saving energy on excavation, processing andtransportation of raw materials.

• Recycles a ‘waste’ by-product of the ironproduction industry that would otherwise go to landfill.

• It replaces primary aggregates, helping toconserve valuable natural resources and habitats.



The Lafarge Reduced Carbon Product RangeBulk Cements

Portland-limestone Cement: (CEM II/A-LL 42,5/52,5)Contains 6-20% of high purity limestone. It conforms to therequirements of BS EN197-1 for CEM IIA-LL cement.

• Similar properties to CEM I cement in respect of carbonationrate, chloride ingress and resistance to freezing and thawing(both air-entrained and non air-entrained concrete).

• Bleeding reduced significantly.

• It has a paler colour and is therefore especially suitable fordecorative and architectural concrete.

Portland-limestone cement is quality assured with independentthird party certification and carries a CE Mark.

Phoenix®:(CEM II/B-V 42,5N)A factory-manufactured sustainable Portland-fly ash cement.Ideal for:

• Large pours, to reduce the risk of early-age thermal cracking.

• Improved surface finish of concrete.

• Reducing attack on concrete in sulfate conditions.

Phoenix Portland-fly ash cement is a quality assured cementwith independent third party certification and carries a CE Mark.

For more detailed information on our cements or any of our other products visit www.lafarge.co.uk

Cemergi™: (CEM III/A 42,5L)Lafarge Cemergi is a factory-produced Blastfurnace cementsuitable for most applications. Compared with Portland cement,it has the following characteristics:

• Improved workability.

• Similar compressive strength.

• Slightly lighter in colour.

Lafarge Cemergi cement has a target blastfurnace slag content of 50%. It is a quality assured cement withindependent third party certification and carries CE marking.


Packed Cements

References British Standards Institution. BS EN 197–1, Cement–Part 1: Composition, specifications and conformity criteria for common cements.British Standards Institution. BS EN 197–4, Cement–Part 4: Composition, specifications and conformity criteria for low early strength blastfurnace cements.

General Purpose Cement: (CEM II 32,5R) A Portland-composite cement suitable for most general purposeapplications. Cement is quality assured to BS EN 197-1 CEM IIwith independent third party certification and carries CE marking.

• Consistent strength meeting all conformity criteria in BS EN 197-1.

• Compatible with admixtures such as air-entraining agentsand workability aids.

Produced using sustainable cement technology and in a rangeof formulations with comparable performance:

Portland-limestone cement (CEM II/A-LL 32,5R)The cement is slightly lighter that CEM I Portland cement, but inother respects its performance is comparable to Portland cement.

Available in 25kg bags throughout the UK.

Portland-fly ash cement (CEM II/B-V 32,5R)The cement is slightly darker than CEM I Portand cement. In most respects its performance is comparable to Portlandcement, but in cold weather, exhibits extended setting time and reduced early strength development.

Mastercrete: (CEM II/A-LL 32,5R) An enhanced Portland-limestone cement with the followingbenefits as compared with ordinary Portland cement.

• Enhanced freeze/thaw resistance.

• Low water demand.

• A more cohesive mix.

• A lower tendency for water to segregate and bleed.

• Tear and weather resistant plastic packaging.

Mastercrete is a quality assured cement with independent thirdparty certification and carries a CE mark.

Available in 25kg and 10kg plastic bags throughout the UK.*

* Independent research has shown that Lafarge plastic packaging is 39%more environmentally friendly than conventional packaging.

Sulfacrete: (CEM II/B-V 32,5R) A Portland-fly ash cement with a high sulfate resistance and a moderate heat of hydration. Particularly suitable for:

• Reducing damage to concrete, mortar and grout exposed tosulfate attack and minimising the risk of alkali-silica reaction.

• Concrete exposed to the marine environment.

Sulfacrete is a low alkali Portland-fly ash cement. This cementis classified by BS 8500 with a +SR suffix, signifying enhancedsulfate resistance. Sulfacrete is a quality assured cement withindependent third party certification and carries a CE Mark.

Available in 25kg bags throughout the UK.

LAFARGE CEMENT UK LTDPortland House, Bickenhill LaneSolihull, Birmingham, B37 7BQTel. 0845 812 6400Fax 0845 812 6200

www.lafarge.co.uk

For further information:Technical helplineTel: 0845 812 6232E-mail: [email protected]

Customer servicesTel: 0845 812 6300E-mail: [email protected]

iPhone Appwww.lafarge.co.uk/iphone

Lafarge and SustainabilityLafarge Cement UK has a long record ofadopting an environmentally friendlyapproach, reflected in a succession ofprestigious awards and acknowl-edgements.

As part of the Environmental Policy andthe Environmental ManagementSystems established under ISO 14001,each of our works develops andimplements a programme of continuousimprovement in environmentalperformance.

A commitment to sustainable sourcingof materials is demonstrated by the factthat Lafarge Cement is the first UKcement producer to be awarded theprestigious BES 6001 ResponsibleSourcing Certificate for our products.

Our Sustain-Able campaign is designedto raise awareness of the importance ofsustainable construction, and toencourage good practice in thesustainable sourcing and use ofmaterials.

For the latest news on our progresstowards a sustainable future, visit outwebsite: www.lafarge.co.uk.

Technical Support

Further information and advice on thisproduct and the full range of LafargeCement products can be obtainedthrough the contacts listed below.Alternatively, step-by-step applicationvideos are available from us on theinternet, by scanning the QR codebelow using your Smartphone or bydownloading our iPhone app from theApp Store.

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