CS 05-CONCRETE WORKS_william Version 10April2012

8/13/2019 CS 05-CONCRETE WORKS_william Version 10April2012

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C&S

SPECIFICATION FOR CIVIL & STRUCTURAL WORKS

Copyright JCP. This document is not to be copied in whole or in part without the written authoritised permission of JCP.JCP shall mean JURO! Consultants Pte "td

5.1.24 CONCRETE COMPRESSIVE STRENGTH TESTS

5.1.24.1 General

The compressi#e strength of concrete shall be measured by crushing tests onnominal $%mm cubes. Tests shall be carried out in any appro#ed "aboratory unlessotherwise appro#ed by the Superintending Officer.

5.1.24.2 Sa!l"n# an$ Te%&"n#

'll sampling( curing and testing of cubes shall be carried out in accordance with)S $**$. ' sample shall be ta+en from a randomly selected batch of concrete chosenby the Superintending Officer. The sample shall be obtained by ta+ing a numberof increments in accordance with )S $**$( and whene#er practicable( at the pointof discharge from the mi,er or ready-mi,ed truc+. our cubes shall be made fromeach sample. Two of these cubes chosen by the Superintending Officer shall be testedat /* days and the a#erage of the two results shall be ta+en as the test result. Theremaining two cubes shall be tested at 0 days.

The Contractor shall pro#ide loc+able watertight curing tan+s of ade1uate si2e tostore all test cubes. The tan+s shall be placed under a co#ered area or at a shadedspot. or precast concrete( two cubes shall be tested at 3 days and the remaining /cubes tested at /* days for compliance purpose. 'dditional cubes shall be ta+en fromthe same sample to determine whether ade1uate strength is achie#ed in order tomeet design strength for demoulding( handling and deli#ery. These additional cubesshall be cured by the same methods as those used for the precast units.


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Copyright JCP. This document is not to be copied in whole or in part without the written authoritised permission of JCP.JCP shall mean JURO! Consultants Pte "td

C&S


5.1.24.' Rae () Sa!l"n# )(r Te%&"n#

On each concreting day( the indicati#e sampling rate shall be as follows4

- $ sample per $m5 or part thereof for critical structures eg masts(cantile#ers( columns

- $ sample per /m5 or part thereof for intermediate structures eg slabs(beams( bridge dec+s

- $ sample per %m5 or part thereof for hea#y concrete construction egbrea+-waters and solid rafts

6n addition to the abo#e( the Superintending Officer may at his absolutediscretion( instruct the Contractor to ta+e additional samples.

7hen a particular grade of concrete from a particular source is used for thefirst time( at least two samples shall be ta+en on the first day so that at least tworesults are a#ailable for compliance determination.

5.1.24.4 C(!l"an*e Re+,"reen&%

Compliance with the specified characteristic strength is attained if themean strength determined from the first two( three or four consecuti#e test results on anygroup of four consecuti#e test results and if each indi#idual test result complieswith the appropriate limits in columns ' and ) of Table %.8 respecti#ely.

7here concrete for the pro9ect is supplied by more than one source( thecompliance determination shall be based on the groups of results analysedseparately from each source.

Ta-le 5. / C(!re%%"0e Sren# C(!l"an*e Re+,"reen&%

Specified !rade

TestResults

'

Specified !rade

TestResults

)

'#erage of first /( of first3( or of : consecuti#e

test results e,ceeds thespecified charac-teristic

strength by at least4

'ny indi#idual testresults is not less than

the charac-teristiccompressi#e strength

minus4

C/&andao#e

irst /

irst 3

$ ;mm/;m3

onthe 1uantity of concrete at ris+ shall be deducted from the Contract Sum.

The 1uantity of concrete at ris+ shall be as defined in %.$./:.%.

7hen successi#e group failure lead to the o#erlap of the 1uantity of concreteat ris+( such 1uantities shall be considered only once.

?eduction of the administrati#e charge shall not relie#e the Contractor of hiscontractual liabilities( including the wor+s stated in %.$./:.8 of Standard Specification.


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5.1.25 TESTS ON HAR8ENE8 CONCRETE

5.1.25.1 C(re Te%&

The Superintending Officer reser#es the right to direct that samples becored from any portion of wor+s for the purpose of e,amination and testing.

The cutting e1uipment and method of coring to obtain specimens shallbe appro#ed by the Superintending Officer.

The specimens shall be dealt with in accordance with )S $**$. Prior topreparation for testing( the specimens shall be made a#ailable for e,amination by theSuperintending Officer.

The cored portion of the wor+s shall be made good to the satisfaction of theSuperintending Officer.

6f the e1ui#alent cube strength of the specimen is less than the appropriatespecified characteristic strength( the concrete represented by the sample shall bedeemed not to comply with the specified re1uirements.

The Contractor shall bear the costs for the core tests if4

- they are re1uired because of wor+ cube test failure( or

- the Superintending Officer ha#ing doubts about the 1uality of concrete(calls for a core test and the core test fails

5.1.25.2 Ce* Te%&

Conse1uent upon wor+ cube test failure( the Superintending Officer may instructthat other appropriate tests be carried out in accordance with )S *$$ on any portion ofthe wor+s for the purpose of assessing the strength. The Contractor shall bear all thecost for such test.

5.1.2 STRUCTURAL TESTS

5.1.2.1 General

The Superintending Officer may direct the Contractor to ma+e a load test on thewor+s or any part thereof if in the Superintending Officer=s opinion such a testis necessary.

6f the test so instructed is to be made because of4

- cube test failure( or

- the finished wor+( in the opinion of the Superintending Officer isstructurally defecti#e and therefore unacceptable unless pro#en otherwise@

then the test shall be made at the Contractor=s e,pense irrespecti#e of the test result.


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Cameron acilit at OAC Tuas South '#enue * C&S B Section % a e no.5


5.1.2.2 L(a$ Te%&

a ,"l$"n# W(r5%

or building wor+s the load test shall be done generally in accordance withBS8110

- 4r"$#e%

The load test shall be the same as that for building wor+s e,cept that the testloads shall be increased by $%.

* Pre*a% Un"&%

Testing of the precast units shall be carried out as and when directed by theSuperintending Officer in accordance with )S *$$. Samples of the precast unit

for the tests shall be pro#ided and deli#ered by the Contractor at his own costto any appro#ed laboratory. The Contractor shall pay for the testing fees ofthe precast units which fail to meet the re1uirements of this Specification.

7here more than one sample from any sample batch of two or moresimilar units fail to satisfy this Specification( then the entire batch of unitsrepresented by such samples shall be liable for re9ection by the SuperintendingOfficer.

or precast concrete members which shall subse1uently form parts of compositemembers( any of the following methods may be used at the discretion of theSuperintending Officer4

$ The precast member may be tested along with a load systeme1ui#alent to that producing the most critical conditions in thecomposite members.

/ The precast member may be made e1ui#alent to the final compositemember by casting the rele#ant amount of in-situ concrete and thentested as a composite member.

5.1.2.' Te% Re%,l&%

6f the result of any of the test is not satisfactory( at the Superintending Officer=sdirection( that part of the wor+s shall be re9ected and reconstructed to comply with thisSpecification( or other appro#ed measures be ta+en to ma+e the wor+s secure( all at theContractor=s e,pense. o e,tension of time shall be entertained in this connection.

CS 05-CONCRETE WORKS_william Version 10April2012

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