Designation:C494/C494M−17StandardSpecificationforChemicalAdmixturesforConcrete1ThisstandardisissuedunderthefixeddesignationC494/C494M;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.ThisstandardhasbeenapprovedforusebyagenciesoftheU.S.DepartmentofDefense.1.Scope*1.1Thisspecificationcoversmaterialsforuseaschemicaladmixturestobeaddedtohydraulic-cementconcretemixturesinthefieldforthepurposeorpurposesindicatedfortheeighttypesasfollows:1.1.1TypeA—Water-reducingadmixtures,1.1.2TypeB—Retardingadmixtures,1.1.3TypeC—Acceleratingadmixtures,1.1.4TypeD—Water-reducingandretardingadmixtures,1.1.5TypeE—Water-reducingandacceleratingadmixtures,1.1.6TypeF—Water-reducing,highrangeadmixtures,1.1.7TypeG—Water-reducing,highrange,andretardingadmixtures,and1.1.8TypeS—Specificperformanceadmixtures.1.2Thisspecificationstipulatestestsofanadmixturewithsuitableconcretingmaterialsasdescribedin11.1–11.3orwithcement,pozzolan,aggregates,andanair-entrainingadmixtureproposedforspecificwork(11.4).Unlessspecifiedotherwisebythepurchaser,thetestsshallbemadeusingconcretingmaterialsasdescribedin11.1–11.3.NOTE1—Itisrecommendedthat,wheneverpracticable,testsbemadeusingthecement,pozzolan,aggregates,air-entrainingadmixture,andthemixtureproportions,batchingsequence,andotherphysicalconditionsproposedforthespecificwork(11.4)becausethespecificeffectsproducedbychemicaladmixturesmayvarywiththepropertiesandproportionsoftheotheringredientsoftheconcrete.Forinstance,TypesFandGadmixturesmayexhibitmuchhigherwaterreductioninconcretemixtureshavinghighercementfactorsthanthatlistedin12.1.1.Mixtureshavingahighrangewaterreductiongenerallydisplayahigherrateofslumploss.Whenhigh-rangeadmixturesareusedtoimpartincreasedworkability(6to8-in.slump[150to200–mm]),theeffectmaybeoflimitedduration,revertingtotheoriginalsl...
