Reducing GHG Emissions withCement UsageReducing GHG Emissions withCement UsageTom Pyle, P.E.Climate Action Team, Cement SubGroup LeaderMarch 25, 2009Technicianin cementlab testingcementEngineers who solve problemsEngineers who solve problemsCement Truck vs a Concrete TruckCement Truck vs a Concrete TruckCement TruckConcrete TruckConcrete placementConcrete placementWhat is the difference?What is the difference?Cement:Concrete:2-6% air11-14% Portland cement16% water26% fine aggregate41% coarse aggregateCourtesy:Portland Cement Association.What is the big deal about acement plant?What is the big deal about acement plant?Cement manufacturing facility..Climate Action TeamClimate Action TeamGovernor’s OfficeCalifornia Environmental Protection AgencyAir Resources BoardAgricultureForestsBusiness/IndustryEnergyWaterTransportationHighGWPGasesRecyclingand WasteManagementStateGov’tGreenbuildingsState fleetLand use/VMTVehiclesFuelsCementSemiconductormanufacturerOil andgas/refiningWhat is cement?What is cement?Cement is the ingredient in concrete thatbinds the rock and sand together to make ahard and durable product.Cement only needs access to water toharden.Cement is made from melting limestonerock, adding some other minerals andmetals, and then letting the new mixture reharden as cement “clinker” in a kiln.What is cement? (cont.)What is cement? (cont.)The clinker is then ground very fine tomake cement powder.The chemical process of changinglimestone to clinker releases CO2intothe atmosphere.Firing the kiln to 3000 degrees alsoreleases greenhouse gasses throughcombustion, just as an automobileengine does.CO2emissions from cementproduction:CO2emissions from cementproduction:~ 7% worldwide.~ 32% in China.~2.5%in California.~ 2% in the U.S.Producing a tonof cementproduces about aton of CO2!Source:Energy Information Administration (2006).California cement production,imports and projectionsCalifornia cement production,imports and projections0246810121416182022 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020

Cement, MMTImportedProducedCalifornia’s GHG ReductionTargetsCalifornia’s GHG ReductionTargets2020:Reduce to 1990 levels,(28% below BAU)2050:Reduce 80% below 1990levels.Magnitude of the ChallengeMagnitude of the ChallengeMagnitude of the Challenge010020030040050060070019902000 201020202050

CO 2 equivalent, MMT1990 emissionbaseline~174 MMT CO2E~341 MMTCO2E80% reductionGHG emission comparisonGHG emission comparisonConcrete truckPassenger carOne concrete truck:5,150 lbs of CO2One car yearly:11,450 lbs of CO2GHG emission comparisonGHG emission comparisonConcrete truckPassenger carOne concrete truck:5,150 lbs of CO2One car yearly:11,450 lbs of CO2Conclusion:2 concrete trucks≅1 car for a yearClinch River, Flyash SpillClinch River, Flyash SpillFly ash: by-product of coal power plantFly ash: by-product of coal power plantCourtesy:Headwaters Resources.Notes.Navajo Generating Station located at Page, AZ.Fly ash class F production:550,000 tons distributedto UT, AR, NE and CA.Clinch River, Flyash SpillClinch River, Flyash SpillSlag: by-product of iron productionSlag: by-product of iron productionCourtesy:Slag Cement Association.Pier table:25% fly ashSCM amount in SFOBB majorelementsSCM amount in SFOBB majorelementsPier column:50% slagPile:35% fly ashPrecast lightweight panels:25% fly ashPrecast fender:20% fly ashLightweight footing cell:60% fly ashWhy SCM?Why SCM?Can substitute cementMakes better concreteDoubly environmental benefits:Reduce GHG emissionsUse recycled productsCost less than cementFly ash(Class C)Fly ash(Class F)SlagMetakaolinSilicafumeCalcinedshaleCaltrans’ use of cement in pavementsand structuresCaltrans’ use of cement in pavementsand structuresOn average, Caltrans uses about 61⁄2“sacks” of cementitious materials (75% ofwhich is cement) per cubic yard ofconcrete.A sack of cement weights 94 pounds.Therefore, about 450 lbs of cement and 150lbs of other cementitious materials are usedper cubic yard of concrete.Reduction in use of cement by Caltransresults in lower greenhouse gas levelsReduction in use of cement by Caltransresults in lower greenhouse gas levelsCaltrans’ goal is to reduce – as soon aspossible – the amount of cement used inpavements and bridges by up to 50%, andyet have stronger, longer-lasting concrete.Some of the cement made from kiln-burnedsources may be replaced in a concretemixture by using other cementitiousmaterials which are mainly recycledproducts.Thus CO2levels will be loweredandwasteproducts used instead of newly producedmaterials.Cement and Supplementary Cementitious MaterialsCement and Supplementary Cementitious MaterialsFly ashMetakaolinGGBF slagSilica fumeCementSource:American Concrete Pavement Association (2004).