【英文标准名称】:StandardGuideforPetrographicExaminationofAggregatesforConcrete
【原文标准名称】:混凝土用集料的岩相检验的标准指南
【标准号】:ASTMC295-2008
【标准状态】:现行
【国别】:美国
【发布日期】:2008
【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】:(Guide)
【标准水平】:()
【中文主题词】:
【英文主题词】:aggregate;analysis;composition;crushedrock;crushedstone;examination;ledgerock;manufacturesand;naturalsand;petrography;quarry;Aggregate;Compositionanalysis;Crushedrock/stone;Drilledconcretecores;Ledgerock;Manufacturedsand;Micros
【摘要】:Petrographicexaminationsaremadeforthefollowingpurposes:Todeterminethephysicalandchemicalcharacteristicsofthematerialthatmaybeobservedbypetrographicmethodsandthathaveabearingontheperformanceofthematerialinitsintendeduse.Todescribeandclassifytheconstituentsofthesample,Todeterminetherelativeamountsoftheconstituentsofthesamplethatareessentialforproperevaluationofthesamplewhentheconstituentsdiffersignificantlyinpropertiesthathaveabearingontheperformanceofthematerialinitsintendeduse,andTocomparesamplesofaggregatefromnewsourceswithsamplesofaggregatefromoneormoresources,forwhichtestdataorperformancerecordsareavailable.Thisguidemaybeusedbyapetrographeremployeddirectlybythoseforwhomtheexaminationismade.Theemployershouldtellthepetrographer,inasmuchdetailasnecessary,thepurposesandobjectivesoftheexamination,thekindofinformationneeded,andtheextentofexaminationdesired.Pertinentbackgroundinformation,includingresultsofpriortesting,shouldbemadeavailable.Thepetrographer''sadviceandjudgmentshouldbesoughtregardingtheextentoftheexamination.Thisguidemayformthebasisforestablishingarrangementsbetweenapurchaserofconsultingpetrographicserviceandthepetrographer.Insuchacase,thepurchaserandtheconsultantshouldtogetherdeterminethekind,extent,andobjectivesoftheexaminationandanalysestobemade,andshouldrecordtheiragreementinwriting.Theagreementmaystipulatespecificdeterminationstobemade,observationstobereported,fundstobeobligated,oracombinationoftheseorotherconditions.Petrographicexaminationofaggregateconsideredforuseinhydraulic-cementconcreteisoneaspectoftheevaluationofaggregate,butpetrographicexaminationisalsousedformanyotherpurposes.Petrographicexaminationsprovideidentificationoftypesandvarietiesofrockspresentinpotentialaggregates.However,asnotedabove,identificationofeveryrockandmineralpresentinanaggregatesourceisnotrequired.Thepetrographicexaminationshouldestablishwhethertheaggregatecontainschemicallyunstablemineralssuchassolublesulfates,unstablesulfidesthatmayformsulfuricacidorcreatedistressinconcreteexposedtohightemperaturesduringservice,orvolumetricallyunstablematerialssuchassmectites(formerlyknownasthemontmorillonite-saponitegroupofmineralsorswellingclays).Specificationsmaylimitthequartzcontentofaggregatesforuseinconcretethatmaybesubjecttohightemperature(purposefullyoraccidentally)becauseoftheconversiontobeta-quartzat573x00B0;C(1063x00B0;F),withaccompanyingvolumeincrease.Petrographicexaminationshouldidentifytheportionofeachcoarseaggregatethatiscomposedofweatheredorotherwisealteredparticlesandtheextentofthatweatheringoralteration,whetheritissevere,moderate,orslight,andshoulddeterminetheproportionofeachrocktypeineachcondition.Iftheconcreteinwhichtheaggregatemaybeusedwillbeexposedtofreezingandthawinginacriticallysaturatedcondition,finelyporousandhighlyweatheredorotherwisealteredrocksshouldbeidentifiedbecausetheywillbeespeciallysusceptibletodamagebyfreezingandthawingandwillcausetheaggregateportionoftheconcretetofailinfreezingandthawing.Thiswillultimatelydestroytheconcretebecausesuchaggregatescannotbeprotectedbyadequatelyair-entrainedmortar.Finelyporousaggregatesneartheconcretesurfacearealsolikelytoformpopouts,whichareblemishesonpavementsandwalls.Petrographicexaminationsmayalsobeusedtodeterminetheproportionsofcubic,spherical,ellipsoidal,pyramid........
【中国标准分类号】:Q13
【国际标准分类号】:91_100_30
【页数】:9P.;A4
【正文语种】:英语