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THEBENEFITSOFUSINGFLYASHFORSUSTAINABLECONCRETEInthepublishedtechnicalliteraturesomeoftheeffectivestrategiestoproducemoresustainableconcreteistoreplaceaportionofthecementcomponentwithoneormoreSCMssuchasyash71216.Thebenetsoftheuseofyashtowardsmoresustainableconstructionmaterialsinclude-ReductioninCO2emissionsandembodiedenergyReductioninresourceuseRe-useofindustrialby-productsasalternativerawmaterialsandSustainabilityachievedthroughefcientdesignandenhanceddurability.ReductioninCO2EmissionsThemanufactureofPortlandCementisanenergyintensiveprocessthatreleasesapproximately0.820tonneofCO2emissionsforeachtonneofcementproduced16.Inastandardconcretemixthecementcomponentcommonlyaccountsforapproximately70to80oftheembodiedenergy.Flyashbeingaby-productofcoalredelectricitygenerationhasarelativelylowembodiedCO2contentrelatedtoitsmanufactureestimatedat0.027kgofCO2emissionspertonne101620thatis3ofPortlandcementmanufacture.InordertobetterillustratethebenetofyashinCO2emissionreductionacomparisonofCO2emissionsfortypical25MPaand50MPaconcretemixeswithincreasingproportionsofyasharepresentedinFigures1and2repsectivelyfollowingreferences1720and21.TheresultsarealsosummarisedinTable1totheright.ReducingthecementcontentinconcretebyincorporationofSCMssuchasyashisarguablythemostefcientandTable1SummaryofCO2emissionreductionsachievablewiththeuseofFlyAsh.Figure1-ComparisonofCO2EmissionsforTypical25MPaConcretesWithVaryingFlyAshContentfollowingreferences1720and21economicalmeansofreducingCO2emissionsandembodiedenergyinconcrete.IndoingthiscareisneededwhenundertakingthistoensurethatotherengineeringdesignandconstructionalrequirementsaremaintainedasdetailedinADAATechnicalNote8andotherindustryguides67.Otherbenetsofusingyashsuchasreducingwaterdemandinconcreteforparticularworkabilityrequirementscanbefactoredinwhenusingyashinconcrete.Forexamplerecentresearchonpost-tensionedslabsinbuildings21andonpretensionedbridgegirders22hasshownthatsimplereductionofPortlandcementinconcretedoesnotnecessarilyresultinloweringembodiedenergyofthestructuralelement.TheADAAhaspublishedadditionaldetailsinADAAReferenceDataSheet923.Throughefcientdesignestablishedstructuralandconstructionalperformancecriteriacanbemetalongwithachievementofreducedelementembodiedenergy.Flyashinclusionsintheconcreteenhancesuchsolutionsforstructuralconstructionalandenvironmentalbenet2021.2