JKRCONCRETESPECIFICATIONS2014

BACKGROUND

• RevisionoftheJKRBuildingSpecificationsstartedin2012involvingCivilengineersandtheArchitects

• Thespecificationswascompleted2014andappliedtoallJKRBuildingprojectsin2015

• CKASandCKJGwereresponsibleforsectionsrelatedtocivilandStructuralEngineeringWorks

• CKASwasresponsibletoSectionD:ConcreteWorks

REASONSFORTHEREVISIONS• UpdateallreferencestotherelevantMalaysian

StandardswhichhasundergonemajorchangesthroughtheadoptionofEuropeanstandards.

• ChangesinMS522MS522(nowMSEN197)seriesoncementandMS523seriesonconcrete

• AdoptiondesignstandardstoMSEN.• Movingforwardfrommethodspecificationto

performancespecification• IntroductionofIBSamustinJKRprojects.• IntroductionofCIS21:2016byCIDB.

MATERIALSINCONCRETE.

• Concrete=Aggregates+cement+water+admixtures• Aggregatesshallbenaturallyoccurringsand,graniteor

limestoneandcomplywithMSEN12620(beforewasMS29).

• Gradingans testingofaggregatesmaintainasinMS30Table2andTable3

MATERIALSINCONCRETE.

• Major changes in the sub section on Cement.• In the old JKR Specification (Rev 2005) there are only 5types of cements namely OPC, RHPC, SRPC,PPFAC(pfa), PSC (slag)

• In the new JKR Specification there are now 27 types ofcements namely 1 type of CEM I, 19 types of CEM II, 3types of CEM III, 2 types of CEM IV and 2 types ofCEM V.

MATERIALSINCONCRETE.

• AdmixturessuppliedshallcomplywithMSEN934/BSEN934-2.

• NotChloridebase.• Theuseofsuper-plasticiserisallowedwithspecialcontrol

testsinaccordancewiththelateststandardandthemanufacturer‘srecommendations.

• AdmixturesacceptancetestasinTableD4.

CLASSIFICATIONSOFCONCRETEMIXES• IntheoldJKRSpecification,twotypesofconcretemixes

arespecifiedwhicharePrescribedMixandDesignedMix.• MS523defines5typesofconcreteie Prescribed

Concrete,DesignedConcrete,DesignatedConcrete,Standardised PrescribedConcrete,andProprietaryConcrete

• Toensurecontinuitywiththeoldspecificationitwasdecidedtocoveronlythefirst2typesofconcreteinthenewJKRspecification.

CLASSIFICATIONSOFCONCRETEMIXES

• PrescribedConcrete andDesignedConcretespecifiedinthenewspcification havebasically,havethesamedefinitionsasPrescribedandDesignedMixrespectively.

• AlltheconcretemixshallcomplywiththerecommendationsofMS523-1andMS523-2.

CLASSIFICATIONSOFCONCRETEMIXES

• PRESCRIBEDCONCRETEmaybeusedfortheworksofminornatureorinvolvingasmallquantityofconcrete.OnlyCEM1cementareallowedandwithnoadmixtures.

• Weightandvolumebatchingareallowed.• TheprescribedconcreteinthenewJKRSpecification

retainsTables5&6oftheoldspecificationcontainingtheformulationforprescribedmixandreproducethemwithoutmodificationinTables5&5A.

CLASSIFICATIONSOFCONCRETEMIXES

• DESIGNEDCONCRETE shallcomplywiththerecommendationsofMS523-1andMS523-2.

• Thedesignedconcreteistobeproducedassitemixedorready-mixed.

• ThemixdesignsubmittedshallcomplywiththerequirementsspecifiedinTABLED6andD6A.

CONCRETEGRADES

• ThedesignedconcretegradetobeusedintheworkshallbeasstatedintheDrawings.

• ConcreteshallbedesignatedasGradeC30/37where‘30'isminimumcharacteristiccylinderstrengthinN/mm2,and‘37'isminimumcharacteristiccubestrengthinN/mm2.

• Forprescribedmix,asuffix'P'shallbeaddedafter‘30').Thedesigned.

CEMENTCONTENT

• TheminimumcementcontentshallbeinaccordancewithTABLED6andD6A,

• Themaximumcementcontentshallnotexceed550kg/m3unlessotherwiseshownontheDrawingsorasapprovedbytheS.O.

CONCRETEDURABILITY

• Inoldspecification,MinimumCementContentandMaximumWater-CementratioinDesignedMixisgovernedbyexposureconditionscategorised bybroaddescriptionsinitstable6.

• InthenewJKRSpecification,theabovevaluesaresimilarlygovernedbyexposureconditionsbutaremoreelaboratelyclassifiedinTableD6.

CONSISTENCEOFCONCRETE• Theconsistenceofthefreshconcreteshallbejudgedby

itssuitabilityfortheconditionofhandlingandplacing.• Consistenceoftheconcreteshallbewithinoneofthe

Limits: (i)Slumpclasses(RefertoTABLED7)(ii)Compactingclasses(RefertoTABLED7A)(iii)Vebe classes(RefertoTABLED7B)(iv)Flowclasses(RefertoTABLED7C)

• ConsistencevaluesexpressedasslumpandflowclassesappropriatetodifferentusesofconcreteshallbeasgiveninTABLED7D.

TargetMeanStrength&CurrentMargin• In the old specification, the contractor is responsible toensure that the concrete mix is designed to have atarget mean strength greater than the required gradeby at least the currentmargin

• The current margin shall be determined by thecontractor as sub-section 3.2.1

TargetMeanStrength&CurrentMargin• In the new JKR Specification it is specified that thetargeted margin should be about twice the standarddeviation which means at least a margin of 6 N/mm2 to12 N/mm2.

• Initially, the standard deviation (σ) shall be calculatedfrom at least 35 consecutive test results taken over aperiod exceeding 3 months and which is immediatelyprior to the production period during which conformityis to be checked.

CONFORMITYANDIDENTITYTESTING• Thecontractorisresponsiblefortheevaluationof

conformityforspecifiedrequirementsoftheconcrete.Forthispurpose,thecontractorshallcarryoutthefollowingtasks:(i)Initialtest,(ii)Productioncontrolincludingconformitycontrol

CONFORMITYANDIDENTITYTESTING• Inthecaseofusinganewconcretecomposition,

initialtestingshallbeperformedtoprovideaconcretethatachievesthespecifiedpropertiesorintendedperformancewithanadequatemargin.

INITIALTEST• In the old specification, the contractor shall carry outTrial Mix as follows• 3 separate batches of concrete• 6 cubes from each batch making a total of 18• 9 cubes tested at 7-day and 9 cubes at 28-day

• Average strength of 9 cubes tested at 28-day• shall exceed the characteristic strength by thecurrentmargin minus 3.5 N/mm2

INITIALTEST• In the new JKR Specification, the contractor shall carryout Initial Test as follows• 3 separate batches of concrete• 3 specimens fromeach batch with a total of 9

• Average strength of 9 cubes tested at 28-day• shall exceed values of fck of Table D8 or D9 at leastby the margin stated earlier

INITIALTEST

SAMPLINGS

SAMPLINGS• In the new specifications, for both compliance testingand conformance testing a sample consists of 3 cubeswhere 1 cube is tested for the 7-day compressivestrength and the remaining 2 cubes are tested for the 28-day compressive strength

• The average strength of the 2 cubes constitutes the 28-day compressive strength of the sample

SAMPLINGS• For the new JKR Specification, in the sampling & testingplan and conformity criteria a distinction is made between• Initial production with less than 35 results• Continuous production with at least 35 resultsobtained over a period not exceeding 12 months

• The minimum rate of sampling and testing of concreteshall be in accordance with table D10

CONFORMITYCRITERIAOFCOMPRESSIVESTRENGTH• In the old specification, for compliance purpose both offollowing conditions must be satisfied• The mean strength determined from first 2, 3 of 4consecutive test results or from any group of 4consecutive results complies with the limits incolumn A of Table 8A of the specs.

• Any individual test result complies with limits incolumn B of Table 8A.

CONFORMITYCRITERIAOFCOMPRESSIVESTRENGTH

• In the new JKR Specification conformity of concretecompressive strength is assessed on specimens tested at28 days in accordance witha) Groups of n non-overlapping or overlapping test

results fcm (Criterion 1)b) Each individual test results fa (Criterion 2)

• Conformity is confirmed if both criteria given in TableD11 for either initial or continuous production aresatisfied.

CONFORMITYCRITERIAOFCOMPRESSIVESTRENGTH

CONFORMITYCRITERIAOFCOMPRESSIVESTRENGTH

IDENTITYTESTING• Identity Testing in the New JKR Specification indicateswhether the defined volume of concrete belongs tosame population which conforms with the specifiedstrength

• JKR decided to adopt the same sampling rate as forcompliance testing in the old specification. In futurethese rates may be reduced once there is moreconfidencewith the concrete producers

IDENTITYTESTING

IDENTITYCRITERIOROFCOMPRESSIVESTRENGTH• In the new JKR Specification for concrete under productioncontrol certification• Identity of concrete is assessed for each individualstrength test result and the average n non-overlappingdiscrete results as identified in Table D13

• Concrete is deemed to come from a conformingpopulation if both criteria in Table D13 are satisfied forn results derived from strength tests on samples

IDENTITYCRITERIOROFCOMPRESSIVESTRENGTH

IDENTITYCRITERIOROFCOMPRESSIVESTRENGTH• For concrete not under production control certification• From the defined volume of concrete, at least 3 samplesshall be taken for testing. The concrete is deemed tocome from a conforming population if conformity forinitial production is satisfied.

IDENTITYCRITERIORFORSLUMPANDFLOW.

CONTROLCHANGEINTHECURRENTMARGIN• In the old specification, recalculation of the margin is carriedout as described in 3.2.1

• The recalculated value is adopted if the two values differ bymore than 18% for tests on 40 batches or more than 11% fortests on 100 batches or more than 5% for tests on 500 batches

CONTROLCHANGEINTHECURRENTMARGIN• In the new JKR Specification, validity of the current marginis verified during subsequent production if the standarddeviation of the latest 15 results S15 does not deviate fromthe initaily adopted standard deviation value (σ) as follows(method 1)

• 0.63σ ≤ S15≤ 1.37σ• Where the value of S15 lies outside this limits a newestimate of σ shall be determined from last available 35test results

CONTROLCHANGEINTHECURRENTMARGIN• Alternatively in the new JKR Specification, provided approvedby S.O. method 2 can be applied whereby a new value of σ isestimated from a continuous system but the sensitivity of thesystem should be at least that of method 1.

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