ASTM C457/C457M-2010 硬化混凝土中空气孔隙系统参数的显微测定用标准试验方法

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【英文标准名称】:StandardTestMethodforMicroscopicalDeterminationofParametersoftheAir-VoidSysteminHardenedConcrete
【原文标准名称】:硬化混凝土中空气孔隙系统参数的显微测定用标准试验方法
【标准号】:ASTMC457/C457M-2010
【标准状态】:现行
【国别】:
【发布日期】:2010
【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】:C09.65
【标准类型】:(TestMethod)
【标准水平】:()
【中文主题词】:空气含量;硬化混凝土中空气孔隙参数;要求的制备区域表面;空隙的平均弦长;空气孔隙参数的测定;产生的空隙;埋陷空隙;硬化混凝土搭叠的研磨粒;指标点;研磨;要求的截线长度;线性截线法;显微镜的;要求的点数;湿黏土-空气比;改良湿黏土-空气比;湿黏土含量;点计数法;显微镜分析的试样制备;空间系数;专用表面;孔隙率;水孔隙;空气含量-混凝土;空气孔隙;硬化水泥;显微镜检验-混凝土;改良点计算法;岩石分析;气孔结果;表面分析-混凝土
【英文主题词】:aircontent;airvoidparametersofhardenedconcrete;area-preparedsurfacerequired;averagechord-lengthofvoids;determinationofair-voidparameters;entrainedvoid;entrappedvoid;gritsforlappinghardenedconcrete;indexpoint;lapping;lengthoftraverserequired;linear-traversemethod;microscopical;numberofpointsrequired;paste-airratio;paste-airratiomodification;pastecontent;point-countmethod(modified);samplepreparationformicroscopicalanalysis;spacingfactor;specificsurface;voidfrequency;watervoid;Aircontent--concrete;Airvoids;Hardenedconcrete;Lineartraverse(Rosiwal)method;Microscopicexamination--concrete;Modifiedpoint-countmethod;Petrographicanalysis;Porestructure;Spacingfactor;Surfaceanalysis--concrete
【摘要】:Theparametersoftheair-voidsystemofhardenedconcretedeterminedbytheproceduresdescribedinthistestmethodarerelatedtothesusceptibilityofthecementpasteportionoftheconcretetodamagebyfreezingandthawing.Hence,thistestmethodcanbeusedtodevelopdatatoestimatethelikelihoodofdamageduetocyclicfreezingandthawingortoexplainwhyithasoccurred.Thetestmethodcanalsobeusedasanadjuncttothedevelopmentofproductsorproceduresintendedtoenhancetheresistanceofconcretetocyclicfreezingandthawing(1).Valuesforparametersoftheair-voidsystemcanbeobtainedbyeitheroftheproceduresdescribedinthistestmethod.Noprovisionismadefordistinguishingamongentrappedairvoids,entrainedairvoids,andwatervoids.Anysuchdistinctionisarbitrary,becausethevarioustypesofvoidsintergradeinsize,shape,andothercharacteristics.Reportsthatdomakesuchadistinctiontypicallydefineentrappedairvoidsasbeinglargerthan1mminatleastonedimensionbeingirregularinshape,orboth.Thehoney-combingthatisaconsequenceofthefailuretocompacttheconcreteproperlyisonetypeofentrappedairvoid(9,10).Watervoidsarecavitiesthatwerefilledwithwateratthetimeofsettingoftheconcrete.Theyaresignificantonlyinmixturesthatcontainedexcessivemixingwaterorinwhichpronouncedbleedingandsettlementoccurred.Theyaremostcommonbeneathhorizontalreinforcingbars,piecesofcoarseaggregateandaschannelwaysalongtheirsides.Theyoccuralsoimmediatelybelowsurfacesthatwerecompactedbyfinishingoperationsbeforethecompletionofbleeding.Applicationofthepaste-airratioprocedureisnecessarywhentheconcreteincludeslargenominalmaximumsizeaggregate,suchas50mm[2in.]ormore.Preparedsectionsofsuchconcreteshouldincludeamaximumofthemortarfraction,soastoincreasethenumberofcountsonairvoidsortraverseacrossthem.Theratioofthevolumeofaggregatetothevolumeofpasteintheoriginalmixmustbeaccuratelyknownorestimatedtopermitthecalculationoftheair-voidsystemsparametersfromthemicroscopicallydeterminedpaste-airratio.Note18212;Theair-voidcontentdeterminedinaccordancewiththistestmethodusuallyagreescloselywiththevaluedeterminedonthefreshconcreteinaccordancewithTestMethodsC138/C138M,C173/C173M,orC231(11).However,significantdifferencesmaybeobservedifthesampleoffreshconcreteisconsolidatedtoadifferentdegreethanthesamplelaterexaminedmicroscopically.Forconcretewitharelativelyhighaircontent(usuallyover7.5%),thevaluedeterminedmicroscopicallymaybehigherbyoneormorepercentagepointsthanthatdeterminedbyTestMethodC231.1.1Thistestmethoddescribesproceduresformicroscopicaldeterminationsoftheaircontentofhardenedconcreteandofthespecificsurface,voidfrequency,spacingfactor,andpaste-airratiooftheair-voidsysteminhardenedconcrete(1).Twoproceduresaredescribed:1.1.1ProcedureA,thelinear-traversemethod(2,3).1.1.2ProcedureB,t......
【中国标准分类号】:
【国际标准分类号】:
【页数】:15P.;A4
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