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1.INTRODUCTIONCoalCombustionProductsCCPsaretheby-productsgeneratedfromthecombustionofpulverisedcoalincoal-redboilersusedforpowergeneration.Theseproductsincludeanercomponentcalledyashandacoarsecomponentcalledfurnacebottomash.Furnacebottomashiscollectedfromthebottomofthecombustionchamberwhilstyashisseparatedfromtheuegasbyeitherelectrostaticprecipitationorfabricltrationpriortothedischargeofthecleanuegasintotheatmosphere.ThereforeCCPsgenerallyfallintotwobroadcategories.InAustraliatheuseofCCPshasincreasedovertime.ThemostcommonbenecialuseofyashisasaSupplementaryCementitiousMaterialSCMinblendedcementandconcretemanufacture12.During2011approximately14milliontonnesofCCPswereproducedinAustraliaofwhichapproximately2milliontonnesofyashwasusedassupplementarycementitiousmaterialsincementbasedandconcreteapplications.Another4milliontonneswasusedinvariouscivilandstructuralapplicationsnotspecicallyaddressedinAustralianStandardsorinStateRoadAuthoritySpecications.ThisreferencedatasheetconsidersthetypesofCCPsthatarecurrentlyproducedatcoalredpowerstationsandthetypesofapplicationswheretheyprovidebenecialuseopportunitiesascomponentsofconstructionmaterials.2.COALCOMBUSTIONPRODUCTSCCPS2.1TYPESANDCLASSIFICATIONAsindicatedCCPsfallintotwobroadgroupsofmaterialsyashandfurnacebottomash.FlyashisdescribedinAustralianStandardAS3582.13asasolidmaterialextractedfromtheuegasesofaboilerredwithpulverizedcoal.WhilsttypicallyusedasanSCMthisdenitionalsoappliestomaterialsnotspecicallycomplyingwiththerequirementsofAS3582.1.Flyashiscomposedofmostlysilicaandaluminiumoxidespeciesbeinganematerialranginginsizebetween1mand300mwitharoundedratherthanangularshape.Itscolourisgenerallylighttomid-greywithanamorphousglassyandnon-crystallinestructureresultinginthematerialhavingpozzolanicpropertiesmeaningthatitwillreactwithcalciumhydroxideproducedbythereactionoflimeorcementandwatertoproduceadditionalcementitiousorbindingcompounds.Thecompositionoftheseparticlesisnotcrystallineandistermedamorphousglassnon-crystalline.Theseamorphousparticlescontributetotheyashhavingpozzolanicproperties12.Furnacebottomashcomprisesmainlyagglomeratedorfusedparticlesthataretoolargetobecarriedintheuegases.Theseparticlesinsteadfalltoanashcollectionpointatthebottomofthefurnace.Furnacebottomasheshaveasimilarchemicalcompositiontoyash.Thereareanumberofsub-classicationsorgradesforyashandfurnacebottomash.Theseare-FlyAshGradesGradedAS3582.1UngradedorRunofStationFurnaceBottomAshGradedUngradedorRunofStationThetermsGradedandUngradedaredescribedbelowGraded-amaterialthathasbeenprocessedselectedorclassiedtomeetspecicgradingandpropertyrequirementsUngraded-amaterialthathasnotbeenprocessedclassiedorselectedtomeetspecicgradingandpropertyrequirementsAshfromeachpowerstationwillhaveuniquepropertiesthataregenerallysuitableforuseasconstructionmaterialcomponents.Signicantquantitiesofmaterialareavailableforfurtherprocessingblendingandapplication.Thesematerialsareavailablefromanumberofsourcesandintheformsdescribedbelow.2.2FLYASHMATERIALAVAILABILITYUngradedyashisseparatedfromuegassesbyelectrostaticprecipitationorfabricltrationpriortotransporttoprocessingfacilitiesorashstoragesiloswhereitbecomesavailableforcollectionandtransport.Ashfromeachpowerstationwillgenerallyexhibitspeciccharacteristicsthatalsomakesitusefulasaconstructionmaterialcomponent.Flyashthatisnotimmediatelyrequiredforbenecialuseisalsoroutinelytransportedtodedicatedashstoragefacilitiesofdifferenttypeslocatedadjacenttothepowerstation.Theseinclude1.DryPlacementUngradedyashisconditionedwithwaterandconveyedbytruckorconveyorforplacement2.DensePhasePlacementUngradedyashismixedwithwatertocreateadensephasematerialspriortopumpingtoanalstoragelocationCoalredpowerstationshavetraditionallyuseddensephaseplacementsystemsduetosimplicityandlowoperatingcosts.Storedmaterialscanberecoveredforbenecialreusebutpropertiesmayneedtobere-assessedpriortouse.FlyAshReferenceDataSheetNO.320131