ASTM C780-2009 普通及钢筋混凝土砌块用灰浆的预施工及施工评定方法

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【英文标准名称】:StandardTestMethodforPreconstructionandConstructionEvaluationofMortarsforPlainandReinforcedUnitMasonry
【原文标准名称】:普通及钢筋混凝土砌块用灰浆的预施工及施工评定方法
【标准号】:ASTMC780-2009
【标准状态】:现行
【国别】:美国
【发布日期】:2009
【实施或试行日期】:
【发布单位】:美国材料与试验协会(US-ASTM)
【起草单位】:C12.02
【标准类型】:(TestMethod)
【标准水平】:()
【中文主题词】:
【英文主题词】:aggregateratio;aircontent;compressivestrength;concretepenetrometer;conepenetrometer;consistency;consistencyretention;mortar;tensilestrength;Aggregateratio;Aggregate-to-cementratio;Aircontent;Compositionanalysis;Compressionte
【摘要】:Duringpreconstructionandconstructionevaluations,useofthesetestmethodsestablishesspecificandoverallperformancecharacteristicsforthemortarsystem.Preconstructiontestingofmortarsprebatchedbyweightprovidesinformationfortheselectionoftheindividualmortarsystembestsuitedforthemasonrytobeconstructed.Therecommendedtestsandtheirsignificanceareasfollows:Consistencydeterminationsbyconepenetrationallowgagingthewateradditionsforallmortarsincludedinthepreconstructiontestseries.Evenifthemortarconsistencyasmeasuredattheconstructionsiteisatadifferentpenetrationvaluethanthosemeasuredduringthepreconstructiontests,theconepreparationtestservestostandardizewateradditionsformortarsbeingconsideredasalternativesbeforeconstruction.Additionaltestingofmortarwatercontent-consistencyrelationships(AnnexA4)willallowrelatingthesetwofactorstobatch-to-batchvariationsattheconstructionsite.Consistencyretentionbyconepenetrationusingdisturbedorundisturbedmortarsamplesprovidesameansofestablishingtheearly-agesettingandstiffeningcharacteristicsofthemortars.Becauselaboratorytestingisconductedunderstaticclimaticconditions,consistencyretentiontestresultsreflecttherelativeperformanceofthemortarsystemsundertest.Thesamegeneralrelationshipsareexpectedtoholdduringtestingattheconstructionproject,exceptastheyareinfluencedbyjobsiteweatherconditions.Mortarwater-contentdeterminations(AnnexA4)allowmeasurementofthewatercontentofthemortarmixture.Mortarsprebatchedusingmoistmasonrysandmaybemathematicallyanalyzedformortarwatercontent;however,thistest,whenusedforpreconstructionevaluation,establishestheeffectivenessofthetestmethodandservesasthecontrolorbasefortestsperformedattheconstructionsite.Mortaraggregateratiotestingprovidesamethodfordeterminingtheratioofaggregate-to-cementitiousmaterials.Thesievingoperationemployedduringthistestisincapableofseparatinganindividualcementitiousmaterialwhenmorethanonesuchmaterialisused,butcanaccuratelyestablishtheaggregate-to-cementitiousmaterialsratioofthemixture.Mortarair-contenttestingisusefulinestablishingthevalueofthiscomponentofthemortar.Thistestisofparticularimportanceinevaluatingmortarsthatcontainair-entrainingportlandcement,air-entraininglime,masonrycementoranycombinationthereof.Compressivestrengthtestingofmoldedmortarcylindersandcubesestablishesoneofthecharacteristicsofhardenedmortar.Mortarcompressivestrengthtestvaluesarenotrepresentativeoftheactualcompressivestrengthofmortarintheassemblyandarenotappropriateforuseinpredictingthecompressivestrengththatwouldbeattainedbythemortarinthemasonryassembly.Themeasuredcompressivestrengthofamoldedmortarspecimenisalmostalwayslowerthanthestrengthofthesamemortarinthewall,primarilyasaresultofdifferencesinmortarwatercontentandspecimenshape.Mortarcompressivestrengthisinfluencedbymortarwatercontentatthetimeofset.Becausemoldedmortarspecimensarenotincontactwithabsorptivemasonryunitsandarenotsubjectedtoothermechanismsofwaterloss,theyhavehigherwatercontentsthanmortarinthewall.Higherwatercontentsalmostalwaysresultinlowerstrengths.Specimensizeandshapealsoaffectcompressivestrength.Cylindersandcubesexhibitdifferentstrengthsevenwhenmadefromthesamemortarmix.Bothofthesespecimenconfigurationsyieldlowerstrengthsthanwhatwouldbeattainedifaspecimenhavingthesamesizeandconfigurationofatypicalmortarjointcouldbereliablytested.Note