C39_C39M-09

StandardTestMethodfor

CompressiveStrengthofCylindricalConcreteSpecimens1ThisstandardisissuedunderthefixeddesignationC39/C39M;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.ThisstandardhasbeenapprovedforusebyagenciesoftheDepartmentofDefense.

1.Scope*

1.1Thistestmethodcoversdeterminationofcompressivestrengthofcylindricalconcretespecimenssuchasmoldedcylindersanddrilledcores.Itislimitedtoconcretehavingaunitweightinexcessof800kg/m3[50lb/ft3].

1.2ThevaluesstatedineitherSIunitsorinch-poundunitsaretoberegardedseparatelyasstandard.TheSIunitsareshowninbrackets.Thevaluesstatedineachsystemmaynotbeexactequivalents;therefore,eachsystemshallbeusedinde-pendentlyoftheother.Combiningvaluesfromthetwosystemsmayresultinnon-conformancewiththestandard.

1.3Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.(Warning—Meansshouldbeprovidedtocontainconcretefragmentsduringsuddenruptureofspecimens.Tendencyforsuddenruptureincreaseswithincreasingconcretestrengthanditismorelikelywhenthetestingmachineisrelativelyflexible.ThesafetyprecautionsgivenintheManualofAggregateandConcreteTestingarerecommended.)

1.4Thetextofthisstandardreferencesnoteswhichprovideexplanatorymaterial.Thesenotesshallnotbeconsideredasrequirementsofthestandard.2.ReferencedDocuments2.1ASTMStandards:2ThistestmethodisunderthejurisdictionofASTMCommitteeC09onConcreteandConcreteAggregatesandisthedirectresponsibilityofSubcommitteeC09.61onTestingforStrength.

CurrenteditionapprovedNov.1,2009.PublishedDecember2009.Originallyapprovedin1921.Lastpreviouseditionapprovedin2005asC39/C39M–05´2.DOI:10.1520/C0039_C0039M-09.2ForreferencedASTMstandards,visittheASTMwebsite,www.astm.org,orcontactASTMCustomerServiceatservice@astm.org.ForAnnualBookofASTMStandardsvolumeinformation,refertothestandard’sDocumentSummarypageontheASTMwebsite.

1C31/C31MPracticeforMakingandCuringConcreteTestSpecimensintheField

C42/C42MTestMethodforObtainingandTestingDrilledCoresandSawedBeamsofConcrete

C192/C192MPracticeforMakingandCuringConcreteTestSpecimensintheLaboratory

C617PracticeforCappingCylindricalConcreteSpecimensC670PracticeforPreparingPrecisionandBiasStatementsforTestMethodsforConstructionMaterials

C873TestMethodforCompressiveStrengthofConcreteCylindersCastinPlaceinCylindricalMolds

C1077PracticeforLaboratoriesTestingConcreteandCon-creteAggregatesforUseinConstructionandCriteriaforLaboratoryEvaluation

C1231/C1231MPracticeforUseofUnbondedCapsinDeterminationofCompressiveStrengthofHardenedCon-creteCylinders

E4PracticesforForceVerificationofTestingMachinesE74PracticeofCalibrationofForce-MeasuringInstru-mentsforVerifyingtheForceIndicationofTestingMa-chines

ManualofAggregateandConcreteTesting

3.SummaryofTestMethod

3.1Thistestmethodconsistsofapplyingacompressiveaxialloadtomoldedcylindersorcoresataratewhichiswithinaprescribedrangeuntilfailureoccurs.Thecompressivestrengthofthespecimeniscalculatedbydividingthemaxi-mumloadattainedduringthetestbythecross-sectionalareaofthespecimen.

4.SignificanceandUse

4.1Caremustbeexercisedintheinterpretationofthesignificanceofcompressivestrengthdeterminationsbythistestmethodsincestrengthisnotafundamentalorintrinsicpropertyofconcretemadefromgivenmaterials.Valuesobtainedwilldependonthesizeandshapeofthespecimen,batching,mixing

*ASummaryofChangessectionappearsattheendofthisstandard.

Copyright©ASTMInternational.100BarrHarborDrive,POboxC-700WestConshohocken,Pennsylvania19428-2959,UnitedStates

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C39/C39M–09

procedures,themethodsofsampling,molding,andfabricationandtheage,temperature,andmoistureconditionsduringcuring.

4.2Thistestmethodisusedtodeterminecompressivestrengthofcylindricalspecimenspreparedandcuredinaccor-dancewithPracticesC31/C31M,C192/C192M,C617,andC1231/C1231MandTestMethodsC42/C42MandC873.4.3Theresultsofthistestmethodareusedasabasisforqualitycontrolofconcreteproportioning,mixing,andplacingoperations;determinationofcompliancewithspecifications;controlforevaluatingeffectivenessofadmixtures;andsimilaruses.

4.4Theindividualwhotestsconcretecylindersforaccep-tancetestingshallmeettheconcretelaboratorytechnicianrequirementsofPracticeC1077,includinganexaminationrequiringperformancedemonstrationthatisevaluatedbyanindependentexaminer.

NOTE1—CertificationequivalenttotheminimumguidelinesforACIConcreteLaboratoryTechnician,LevelIorACIConcreteStrengthTestingTechnicianwillsatisfythisrequirement.

5.1.3.1Thepercentageoferrorfortheloadswithintheproposedrangeofuseofthetestingmachineshallnotexceed61.0%oftheindicatedload.

5.1.3.2Theaccuracyofthetestingmachineshallbeverifiedbyapplyingfivetestloadsinfourapproximatelyequalincrementsinascendingorder.Thedifferencebetweenanytwosuccessivetestloadsshallnotexceedonethirdofthediffer-encebetweenthemaximumandminimumtestloads.

5.1.3.3Thetestloadasindicatedbythetestingmachineandtheappliedloadcomputedfromthereadingsoftheverificationdeviceshallberecordedateachtestpoint.Calculatetheerror,E,andthepercentageoferror,Ep,foreachpointfromthesedataasfollows:

E5A2BEp5100~A2B!/B

(1)

5.Apparatus

5.1TestingMachine—Thetestingmachineshallbeofatypehavingsufficientcapacityandcapableofprovidingtheratesofloadingprescribedin7.5.

5.1.1Verifycalibrationofthetestingmachinesinaccor-dancewithPracticesE4,exceptthattheverifiedloadingrangeshallbeasrequiredin5.3.Verificationisrequiredunderthefollowingconditions:

5.1.1.1Atleastannually,butnottoexceed13months,5.1.1.2Onoriginalinstallationorimmediatelyafterreloca-tion,

5.1.1.3Immediatelyaftermakingrepairsoradjustmentsthataffecttheoperationoftheforceapplyingsystemorthevaluesdisplayedontheloadindicatingsystem,exceptforzeroadjustmentsthatcompensateforthemassofbearingblocksorspecimen,orboth,or

5.1.1.4Wheneverthereisreasontosuspecttheaccuracyoftheindicatedloads.

5.1.2Design—Thedesignofthemachinemustincludethefollowingfeatures:

5.1.2.1Themachinemustbepoweroperatedandmustapplytheloadcontinuouslyratherthanintermittently,andwithoutshock.Ifithasonlyoneloadingrate(meetingtherequirementsof7.5),itmustbeprovidedwithasupplementalmeansforloadingataratesuitableforverification.Thissupplementalmeansofloadingmaybepowerorhandoper-ated.

5.1.2.2Thespaceprovidedfortestspecimensshallbelargeenoughtoaccommodate,inareadableposition,anelasticcalibrationdevicewhichisofsufficientcapacitytocoverthepotentialloadingrangeofthetestingmachineandwhichcomplieswiththerequirementsofPracticeE74.

NOTE2—Thetypesofelasticcalibrationdevicesmostgenerallyavail-ableandmostcommonlyusedforthispurposearethecircularprovingringorloadcell.

where:

A=load,kN[lbf]indicatedbythemachinebeingverified,

and

B=appliedload,kN[lbf]asdeterminedbythecalibrating

device.

5.1.3.4Thereportontheverificationofatestingmachineshallstatewithinwhatloadingrangeitwasfoundtoconformtospecificationrequirementsratherthanreportingablanketacceptanceorrejection.Innocaseshalltheloadingrangebestatedasincludingloadsbelowthevaluewhichis100timesthesmallestchangeofloadestimableontheload-indicatingmechanismofthetestingmachineorloadswithinthatportionoftherangebelow10%ofthemaximumrangecapacity.5.1.3.5Innocaseshalltheloadingrangebestatedasincludingloadsoutsidetherangeofloadsappliedduringtheverificationtest.

5.1.3.6Theindicatedloadofatestingmachineshallnotbecorrectedeitherbycalculationorbytheuseofacalibrationdiagramtoobtainvalueswithintherequiredpermissiblevariation.

5.2Thetestingmachineshallbeequippedwithtwosteelbearingblockswithhardenedfaces(Note3),oneofwhichisasphericallyseatedblockthatwillbearontheuppersurfaceofthespecimen,andtheotherasolidblockonwhichthespecimenshallrest.Bearingfacesoftheblocksshallhaveaminimumdimensionatleast3%greaterthanthediameterofthespecimentobetested.Exceptfortheconcentriccirclesdescribedbelow,thebearingfacesshallnotdepartfromaplanebymorethan0.02mm[0.001in.]inany150mm[6in.]ofblocks150mm[6in.]indiameterorlarger,orbymorethan0.02mm[0.001in.]inthediameterofanysmallerblock;andnewblocksshallbemanufacturedwithinonehalfofthistolerance.Whenthediameterofthebearingfaceofthesphericallyseatedblockexceedsthediameterofthespecimenbymorethan13mm[0.5in.],concentriccirclesnotmorethan0.8mm[0.03in.]deepandnotmorethan1mm[0.04in.]wideshallbeinscribedtofacilitatepropercentering.

NOTE3—ItisdesirablethatthebearingfacesofblocksusedforcompressiontestingofconcretehaveaRockwellhardnessofnotlessthan55HRC.

5.1.3Accuracy—Theaccuracyofthetestingmachineshallbeinaccordancewiththefollowingprovisions:

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5.2.1Bottombearingblocksshallconformtothefollowingrequirements:

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5.2.1.1Thebottombearingblockisspecifiedforthepur-poseofprovidingareadilymachinablesurfaceformainte-nanceofthespecifiedsurfaceconditions(Note4).Thetopandbottomsurfacesshallbeparalleltoeachother.Ifthetestingmachineissodesignedthattheplatenitselfisreadilymain-tainedinthespecifiedsurfacecondition,abottomblockisnotrequired.Itsleasthorizontaldimensionshallbeatleast3%greaterthanthediameterofthespecimentobetested.Concentriccirclesasdescribedin5.2areoptionalonthebottomblock.

NOTE4—Theblockmaybefastenedtotheplatenofthetestingmachine.

5.2.1.2Finalcenteringmustbemadewithreferencetotheuppersphericalblock.Whenthelowerbearingblockisusedtoassistincenteringthespecimen,thecenteroftheconcentricrings,whenprovided,orthecenteroftheblockitselfmustbedirectlybelowthecenterofthesphericalhead.Provisionshallbemadeontheplatenofthemachinetoassuresuchaposition.5.2.1.3Thebottombearingblockshallbeatleast25mm[1in.]thickwhennew,andatleast22.5mm[0.9in.]thickafteranyresurfacingoperations.

5.2.2Thesphericallyseatedbearingblockshallconformtothefollowingrequirements:

5.2.2.1Themaximumdiameterofthebearingfaceofthesuspendedsphericallyseatedblockshallnotexceedthevaluesgivenbelow:

DiameterofTestSpecimens,

mm[in.]

50[2]75[3]100[4]150[6]200[8]

MaximumDiameterofBearingFace,

mm[in.]

105[4]130[5]165[6.5]255[10]280[11]

NOTE—Provisionshallbemadeforholdingtheballinthesocketandforholdingtheentireunitinthetestingmachine.

FIG.1SchematicSketchofaTypicalSphericalBearingBlock

NOTE5—Squarebearingfacesarepermissible,providedthediameterofthelargestpossibleinscribedcircledoesnotexceedtheabovediameter.

5.2.2.2Thecenterofthesphereshallcoincidewiththesurfaceofthebearingfacewithinatoleranceof65%oftheradiusofthesphere.Thediameterofthesphereshallbeatleast75%ofthediameterofthespecimentobetested.

5.2.2.3Theballandthesocketshallbedesignedsothatthesteelinthecontactareadoesnotpermanentlydeformwhenloadedtothecapacityofthetestingmachine.

NOTE6—Thepreferredcontactareaisintheformofaring(describedas“preferredbearingarea”)asshownonFig.1.

5.2.2.4Thecurvedsurfacesofthesocketandofthespheri-calportionshallbekeptcleanandshallbelubricatedwithapetroleum-typeoilsuchasconventionalmotoroil,notwithapressuretypegrease.Aftercontactingthespecimenandappli-cationofsmallinitialload,furthertiltingofthesphericallyseatedblockisnotintendedandisundesirable.

5.2.2.5Iftheradiusofthesphereissmallerthantheradiusofthelargestspecimentobetested,theportionofthebearingfaceextendingbeyondthesphereshallhaveathicknessnotlessthanthedifferencebetweentheradiusofthesphereandradiusofthespecimen.Theleastdimensionofthebearingfaceshallbeatleastasgreatasthediameterofthesphere(seeFig.1).

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5.2.2.6Themovableportionofthebearingblockshallbeheldcloselyinthesphericalseat,butthedesignshallbesuchthatthebearingfacecanberotatedfreelyandtiltedatleast4°inanydirection.

5.2.2.7Iftheballportionoftheupperbearingblockisatwo-piecedesigncomposedofasphericalportionandabearingplate,amechanicalmeansshallbeprovidedtoensurethatthesphericalportionisfixedandcenteredonthebearingplate.

5.3LoadIndication:

5.3.1Iftheloadofacompressionmachineusedinconcretetestingisregisteredonadial,thedialshallbeprovidedwithagraduatedscalethatisreadabletoatleastthenearest0.1%ofthefullscaleload(Note7).Thedialshallbereadablewithin1%oftheindicatedloadatanygivenloadlevelwithintheloadingrange.Innocaseshalltheloadingrangeofadialbeconsideredtoincludeloadsbelowthevaluethatis100timesthesmallestchangeofloadthatcanbereadonthescale.Thescaleshallbeprovidedwithagraduationlineequaltozeroandsonumbered.Thedialpointershallbeofsufficientlengthtoreachthegraduationmarks;thewidthoftheendofthepointershallnotexceedthecleardistancebetweenthesmallestgraduations.Eachdialshallbeequippedwithazeroadjust-mentlocatedoutsidethedialcaseandeasilyaccessiblefromthefrontofthemachinewhileobservingthezeromarkanddialpointer.Eachdialshallbeequippedwithasuitabledevicethatatalltimes,untilreset,willindicatetowithin1%accuracythemaximumloadappliedtothespecimen.

NOTE7—Readabilityisconsideredtobe0.5mm[0.02in.]alongthearcdescribedbytheendofthepointer.Also,onehalfofascaleintervalisreadablewithreasonablecertaintywhenthespacingontheloadindicatingmechanismisbetween1mm[0.04in.]and2mm[0.06in.].Whenthespacingisbetween2and3mm[0.06and0.12in.],onethirdofascaleintervalisreadablewithreasonablecertainty.Whenthespacingis3mm[0.12in.]ormore,onefourthofascaleintervalisreadablewithreasonablecertainty.

5.3.2Ifthetestingmachineloadisindicatedindigitalform,thenumericaldisplaymustbelargeenoughtobeeasilyread.

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Thenumericalincrementmustbeequaltoorlessthan0.10%ofthefullscaleloadofagivenloadingrange.Innocaseshalltheverifiedloadingrangeincludeloadslessthantheminimumnumericalincrementmultipliedby100.Theaccuracyoftheindicatedloadmustbewithin1.0%foranyvaluedisplayedwithintheverifiedloadingrange.Provisionmustbemadeforadjustingtoindicatetruezeroatzeroload.Thereshallbeprovidedamaximumloadindicatorthatatalltimesuntilresetwillindicatewithin1%systemaccuracythemaximumloadappliedtothespecimen.6.Specimens

6.1Specimensshallnotbetestedifanyindividualdiameterofacylinderdiffersfromanyotherdiameterofthesamecylinderbymorethan2%.

NOTE8—Thismayoccurwhensingleusemoldsaredamagedordeformedduringshipment,whenflexiblesingleusemoldsaredeformedduringmolding,orwhenacoredrilldeflectsorshiftsduringdrilling.

6.5Whendensitydeterminationisnotrequiredandthelengthtodiameterratioislessthan1.8ormorethan2.2,measurethelengthofthespecimentothenearest0.05D.7.Procedure

7.1Compressiontestsofmoist-curedspecimensshallbemadeassoonaspracticableafterremovalfrommoiststorage.7.2Testspecimensshallbekeptmoistbyanyconvenientmethodduringtheperiodbetweenremovalfrommoiststorageandtesting.Theyshallbetestedinthemoistcondition.

7.3Alltestspecimensforagiventestageshallbebrokenwithinthepermissibletimetolerancesprescribedasfollows:

TestAge24372890hdaysdaysdaysdays

PermissibleTolerance60.5

26202

hor2.1%hor2.8%hor3.6%hor3.0%days2.2%

6.2Priortotesting,neitherendoftestspecimensshalldepartfromperpendicularitytotheaxisbymorethan0.5°(approximatelyequivalentto1mmin100mm[0.12in.in12in.]).Theendsofcompressiontestspecimensthatarenotplanewithin0.050mm[0.002in.]shallbesawedorgroundtomeetthattolerance,orcappedinaccordancewitheitherPracticeC617or,whenpermitted,PracticeC1231/C1231M.Thediam-eterusedforcalculatingthecross-sectionalareaofthetestspecimenshallbedeterminedtothenearest0.25mm[0.01in.]byaveragingtwodiametersmeasuredatrightanglestoeachotherataboutmidheightofthespecimen.

6.3Thenumberofindividualcylindersmeasuredfordeter-minationofaveragediameterisnotprohibitedfrombeingreducedtooneforeachtenspecimensorthreespecimensperday,whicheverisgreater,ifallcylindersareknowntohavebeenmadefromasinglelotofreusableorsingle-usemoldswhichconsistentlyproducespecimenswithaveragediameterswithinarangeof0.5mm[0.02in.].Whentheaveragediametersdonotfallwithintherangeof0.5mm[0.02in.]orwhenthecylindersarenotmadefromasinglelotofmolds,eachcylindertestedmustbemeasuredandthevalueusedincalculationoftheunitcompressivestrengthofthatspecimen.Whenthediametersaremeasuredatthereducedfrequency,thecross-sectionalareasofallcylinderstestedonthatdayshallbecomputedfromtheaverageofthediametersofthethreeormorecylindersrepresentingthegrouptestedthatday.

6.4Ifthepurchaserofthetestingservicesrequestsmeasure-mentofdensityoftestspecimens,determinethemassofspecimensbeforecapping.Removeanysurfacemoisturewithatowelandmeasurethemassofthespecimenusingabalanceorscalethatisaccuratetowithin0.3%ofthemassbeingmeasured.Measurethelengthofthespecimentothenearest1mm[0.05in.]atthreelocationsspacedevenlyaroundthecircumference.Computetheaveragelengthandrecordtothenearest1mm[0.05in.].Alternatively,determinethecylinderdensitybyweighingthecylinderinairandthensubmergedunderwaterat23.062.0°C[73.563.5°F],andcomputingthevolumeaccordingto8.3.1.

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7.4PlacingtheSpecimen—Placetheplain(lower)bearingblock,withitshardenedfaceup,onthetableorplatenofthetestingmachinedirectlyunderthesphericallyseated(upper)bearingblock.Wipecleanthebearingfacesoftheupperandlowerbearingblocksandofthetestspecimenandplacethetestspecimenonthelowerbearingblock.Carefullyaligntheaxisofthespecimenwiththecenterofthrustofthesphericallyseatedblock.

7.4.1ZeroVerificationandBlockSeating—Priortotestingthespecimen,verifythattheloadindicatorissettozero.Incaseswheretheindicatorisnotproperlysettozero,adjusttheindicator(Note9).Asthesphericallyseatedblockisbroughttobearonthespecimen,rotateitsmovableportiongentlybyhandsothatuniformseatingisobtained.

NOTE9—Thetechniqueusedtoverifyandadjustloadindicatortozerowillvarydependingonthemachinemanufacturer.Consultyourowner’smanualorcompressionmachinecalibratorforthepropertechnique.

7.5RateofLoading—Applytheloadcontinuouslyandwithoutshock.

7.5.1Theloadshallbeappliedatarateofmovement(platentocrossheadmeasurement)correspondingtoastressrateonthespecimenof0.2560.05MPa/s[3567psi/s](SeeNote10).Thedesignatedrateofmovementshallbemaintainedatleastduringthelatterhalfoftheanticipatedloadingphase.

NOTE10—Forascrew-drivenordisplacement-controlledtestingma-chine,preliminarytestingwillbenecessarytoestablishtherequiredrateofmovementtoachievethespecifiedstressrate.Therequiredrateofmovementwilldependonthesizeofthetestspecimen,theelasticmodulusoftheconcrete,andthestiffnessofthetestingmachine.

7.5.2Duringapplicationofthefirsthalfoftheanticipatedloadingphase,ahigherrateofloadingshallbepermitted.Thehigherloadingrateshallbeappliedinacontrolledmannersothatthespecimenisnotsubjectedtoshockloading.

7.5.3Makenoadjustmentintherateofmovement(platentocrosshead)astheultimateloadisbeingapproachedandthestressratedecreasesduetocrackinginthespecimen.

7.6Applythecompressiveloaduntiltheloadindicatorshowsthattheloadisdecreasingsteadilyandthespecimendisplaysawell-definedfracturepattern(Types1to4inFig.2).Foratestingmachineequippedwithaspecimenbreakdetector,

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FIG.2SchematicofTypicalFracturePatterns

automaticshut-offofthetestingmachineisprohibiteduntiltheloadhasdroppedtoavaluethatislessthan95%ofthepeakload.Whentestingwithunbondedcaps,acornerfracturesimilartoaType5or6patternshowninFig.2mayoccurbeforetheultimatecapacityofthespecimenhasbeenattained.Continuecompressingthespecimenuntiltheuseriscertainthattheultimatecapacityhasbeenattained.Recordthemaximumloadcarriedbythespecimenduringthetest,andnotethetypeoffracturepatternaccordingtoFig.2.IfthefracturepatternisnotoneofthetypicalpatternsshowninFig.2,sketchanddescribebrieflythefracturepattern.Ifthemeasuredstrengthislowerthanexpected,examinethefrac-turedconcreteandnotethepresenceoflargeairvoids,evidenceofsegregation,whetherfracturespasspredominantlyaroundorthroughthecoarseaggregateparticles,andverifyendpreparationswereinaccordancewithPracticeC617orPracticeC1231/C1231M.

8.Calculation

8.1Calculatethecompressivestrengthofthespecimenbydividingthemaximumloadcarriedbythespecimenduringthetestbytheaveragecross-sectionalareadeterminedasde-scribedinSection6andexpresstheresulttothenearest0.1MPa[10psi].

5

8.2Ifthespecimenlengthtodiameterratiois1.75orless,correcttheresultobtainedin8.1bymultiplyingbytheappropriatecorrectionfactorshowninthefollowingtableNote11:

L/D:Factor:

1.750.98

1.500.96

1.250.93

1.000.87

UseinterpolationtodeterminecorrectionfactorsforL/Dvaluesbetweenthosegiveninthetable.

NOTE11—Correctionfactorsdependonvariousconditionssuchasmoisturecondition,strengthlevel,andelasticmodulus.Averagevaluesaregiveninthetable.Thesecorrectionfactorsapplytolow-densityconcreteweighingbetween1600and1920kg/m3[100and120lb/ft3]andtonormal-densityconcrete.Theyareapplicabletoconcretedryorsoakedatthetimeofloadingandfornominalconcretestrengthsfrom14to42MPa[2000to6000psi].Forstrengthshigherthan42MPai[6000ps]correctionfactorsmaybelargerthanthevalueslistedabove3.

8.3Whenrequired,calculatethedensityofthespecimentothenearest10kg/m3[1lb/ft3]asfollows:

W

Density5V3(2)

Bartlett,F.M.andMacGregor,J.G.,“EffectofCoreLength-to-DiameterRatioonConcreteCoreStrength,”ACIMaterialsJournal,Vol91,No.4,July-August,1994,pp.339-348.

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where:

W=massofspecimen,kg[lb],and

V=volumeofspecimencomputedfromtheaverage

diameterandaveragelengthorfromweighingthecylinderinairandsubmerged,m3[ft3]

8.3.1Whenthevolumeisdeterminedfromsubmergedweighing,calculatethevolumeasfollows:

V5

W–Wsgw

(3)

where:

Ws=apparentmassofsubmergedspecimen,kg[lb],andgw=densityofwaterat23°C[73.5°F]=997.5kg/m3[62.27lbs/ft3].9.Report

9.1Reportthefollowinginformation:9.1.1Identificationnumber,

9.1.2Diameter(andlength,ifoutsidetherangeof1.8Dto2.2D),inmillimetres[inches],

9.1.3Cross-sectionalarea,insquaremillimetres[squareinches],

9.1.4Maximumload,inkilonewtons[pounds-force],

9.1.5Compressivestrengthcalculatedtothenearest0.1MPa[10psi],

9.1.6Typeoffracture,ifotherthantheusualcone(seeFig.2),

9.1.7Defectsineitherspecimenorcaps,and,9.1.8Ageofspecimen.

9.1.9Whendetermined,thedensitytothenearest10kg/3m[1lb/ft3].

10.PrecisionandBias10.1Precision

10.1.1Within-TestPrecision—Thefollowingtableprovidesthewithin-testprecisionoftestsof150by300mm[6by12in.]and100by200mm[4by8in.]cylindersmadefromawell-mixedsampleofconcreteunderlaboratoryconditionsandunderfieldconditions(see10.1.2).

CoefficientofVariation4150by300mm[6by12in.]

LaboratoryconditionsFieldconditions100by200mm[4by8in.]

Laboratoryconditions

AcceptableRange4ofIndividualCylinderStrengths2cylinders3cylinders

10.1.2Thewithin-testcoefficientofvariationrepresentsthe

expectedvariationofmeasuredstrengthofcompanioncylin-derspreparedfromthesamesampleofconcreteandtestedbyonelaboratoryatthesameage.Thevaluesgivenforthewithin-testcoefficientofvariationof150by300mm[6by12in.]cylindersareapplicableforcompressivestrengthsbetween2000and15to55MPa[8000psi]andthosefor100by200mm[4by8in.]cylindersareapplicableforcompressivestrengthsbetween17to32MPa[2500and4700psi].Thewithin-testcoefficientsofvariationfor150by300mm[6by12in.]cylindersarederivedfromCCRLconcreteproficiencysampledataforlaboratoryconditionsandacollectionof1265testreportsfrom225commercialtestinglaboratoriesin1978.5Thewithin-testcoefficientofvariationof100by200mm[4by8in.]cylindersarederivedfromCCRLconcreteproficiencysampledataforlaboratoryconditions.

10.1.3MultilaboratoryPrecision—Themulti-laboratorycoefficientofvariationforcompressivestrengthtestresultsof150by300mm[6by12in.]cylindershasbeenfoundtobe5.0%4;therefore,theresultsofproperlyconductedtestsbytwolaboratoriesonspecimenspreparedfromthesamesampleofconcretearenotexpectedtodifferbymorethan14%4oftheaverage(SeeNote12).Astrengthtestresultistheaverageoftwocylinderstestedatthesameage.

NOTE12—Themultilaboratoryprecisiondoesnotincludevariationsassociatedwithdifferentoperatorspreparingtestspecimensfromsplitorindependentsamplesofconcrete.Thesevariationsareexpectedtoincreasethemultilaboratorycoefficientofvariation.

10.1.4Themultilaboratorydatawereobtainedfromsixseparateorganizedstrengthtestingroundrobinprogramswhere150x300mm[6x12in.]cylindricalspecimenswerepreparedatasinglelocationandtestedbydifferentlaborato-ries.Therangeofaveragestrengthfromtheseprogramswas17.0to90MPa[2500to13000psi].

NOTE13—SubcommitteeC09.61willcontinuetoexaminerecentconcreteproficiencysampledataandfieldtestdataandmakerevisionstoprecisionsstatementswhendataindicatethattheycanbeextendedtocoverawiderrangeofstrengthsandspecimensizes.

2.4%2.9%6.6%8.0%7.8%9.5%

10.2Bias—Sincethereisnoacceptedreferencematerial,nostatementonbiasisbeingmade.

3.2%9.0%10.6%

Thesenumbersrepresentrespectivelythe(1s%)and(d2s%)limitsasdescribedinPracticeC670.

4SupportingdatahavebeenfiledatASTMInternationalHeadquartersandmaybeobtainedbyrequestingResearchReportC09-1006.

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SUMMARYOFCHANGES

CommitteeC09hasidentifiedthelocationofselectedchangestothistestmethodsincethelastissue,C39/C39M–05´2,thatmayimpacttheuseofthistestmethod.

(1)RevisedNote6toclarifythereferencetoFig.1.

ASTMInternationaltakesnopositionrespectingthevalidityofanypatentrightsassertedinconnectionwithanyitemmentionedinthisstandard.Usersofthisstandardareexpresslyadvisedthatdeterminationofthevalidityofanysuchpatentrights,andtheriskofinfringementofsuchrights,areentirelytheirownresponsibility.

Thisstandardissubjecttorevisionatanytimebytheresponsibletechnicalcommitteeandmustbereviewedeveryfiveyearsandifnotrevised,eitherreapprovedorwithdrawn.YourcommentsareinvitedeitherforrevisionofthisstandardorforadditionalstandardsandshouldbeaddressedtoASTMInternationalHeadquarters.Yourcommentswillreceivecarefulconsiderationatameetingoftheresponsibletechnicalcommittee,whichyoumayattend.IfyoufeelthatyourcommentshavenotreceivedafairhearingyoushouldmakeyourviewsknowntotheASTMCommitteeonStandards,attheaddressshownbelow.

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