Designation:C90−16aStandardSpecificationforLoadbearingConcreteMasonryUnits1ThisstandardisissuedunderthefixeddesignationC90;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.ThisstandardhasbeenapprovedforusebyagenciesoftheU.S.DepartmentofDefense.1.Scope*1.1Thisspecificationcovershollowandsolid(see5.3and5.4)concretemasonryunitsmadefromhydrauliccement,water,andmineralaggregateswithorwithouttheinclusionofothermaterials.Therearethreeclassesofconcretemasonryunits:NormalWeight,MediumWeight,andLightweight.Theseunitsaresuitableforbothloadbearingandnonloadbear-ingapplications.1.2Concretemasonryunitscoveredbythisspecificationaremadefromlightweightornormalweightaggregates,orboth.NOTE1—Therequirementsofthisspecificationhavebeenresearched,evaluated,andestablishedforoveracentury,resultinginthephysicalpropertiesandattributesdefinedhere.Theserequirementsareuniquelyandsolelyapplicabletoconcretemasonryunitsmanufacturedonequip-mentusingloworzeroslumpconcreteandtheconstituentmaterialsdefinedherein.Manyperformanceattributesofconcretemasonryunitsareindirectlyaccountedfor,orinherentlyreflectedwithin,therequirementsofthisspecificationwithoutdirectmeasurement,assessment,orevalua-tion.Applyingtherequirementsofthisspecificationtoproductsthatmaybesimilarinappearance,use,ornaturetothosecoveredbythisspecificationmaynotaddressallpertinentphysicalpropertiesnecessarytoensureperformanceorserviceabilityoftheresultingconstructioninreal-worldapplicationsundertypicalexposureenvironments.Productsmanufacturedusingalternativematerials,manufacturingmethods,orcuringprocessesnotcoveredbythisspecificationshouldnotbeevaluatedsolelyusingtherequirementsinthisspecification;however,developersofnewproductscanconsiderthepropertyrequirementsofthisspecificationasabeginningbenchmarkforunitperformance.Itisreasonab...
