ASTM_C_172-C172M-14a.pdf

Designation:C172/C172M-14aINTERNATIONALStandard Practice forSampling Freshly Mixed Concrete1This standard is issued under the fixed designation C172/C172M:the number immediately following the designation indicates the yearof original adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.A superscript epsilon(s)indicates an editorial change since the last revision or reapproval.1.Scopehydraulic cementitious mixtures are caustic and may cause1.1 This practice covers procedures for obtaining represen-chemical burns to skin and tissue upon prolonged exposure.2)tative samples of fresh concrete as delivered to the project siteon which tests are to be performed to determine compliance2.Referenced Documentswith quality requirements of the specifications under which the2.1 ASTM Standards:3concrete is furnished(Note 1).The practice includes samplingEll Specification for Woven Wire Test Sieve Cloth and Testfrom stationary,paving and truck mixers,and from agitatingSievesand nonagitating equipment used to transport central-mixedC685/C685M Specification for Concrete Made by Volumet-concrete and from continuous mixing equipment as describedric Batching and Continuous Mixingin Specification C685/C685M.1.2 The values stated in either SI units or inch-pound units3.Significance and Useare to be regarded separately as standard.The values stated in3.1 This practice is intended to provide standard require-each system may not be exact equivalents:therefore,eachments and procedures for sampling freshly mixed concretesystem shall be used independently of the other.Combiningfrom different containers used in the production or transporta-values from the two systems may result in non-conformancetion of concrete.The detailed requirements as to materials,with the standard.mixtures,air content,temperature,number of specimens,NorE 1-Composite samples are required by this practice,unlessslump,interpretation of results,and precision and bias are inspecifically excepted by procedures governing the tests to be performedspecific test methods.such as tests to determine uniformity of consistency and mixer efficiency.Procedures used to select the specific test batches are not described in this4.Samplingpractice,but it is recommended that random sampling be used todeteriine overall specification compliance.4.1 The elapsed time shall not exceed 15 min.between1.3 This practice also covers the procedures to be used forobtaining the first and final portions of the composite sample.preparing a sample of concrete for further testing where it is4.1.1 Transport the individual samples to the place wheredesirable or necessary to remove the aggregate larger than afresh concrete tests are to be performed or where test speci-designated size.This removal of larger aggregate particles ismens are to be molded.They shall be combined and remixedpreferably accomplished by wet-sieving.with a shovel the minimum amount necessary to ensureuniformity and compliance with the maximum time limits1.4 The text of this standard references notes and footnotesspecified in 4.1.2.which provide explanatory material and shall not be consideredas requirements of the practice.4.1.2 Start tests for slump,temperature,and air contentwithin 5 min after obtaining the final portion of the composite1.5 This standard does not purport to address all of thesample.Complete these tests expeditiously.Start moldingsafety concerns,if any,associated with its use.It is thespecimens for strength tests within 15 min after fabricating theresponsibility of the user of this standard to establish appro-composite sample.Expeditiously obtain and use the samplepriate safery and health practices and determine the applica-and protect the sample from the sun,wind,and other sources ofbility of regulatory limitations prior to use.(Warning-Freshrapid evaporation,and from contamination.This practice is under the jurisdiction of ASTM Committee C09 on Concrete2 Section on Safety Precautions,Manual of Aggregate and Concrete Testing.and Concrete Aggregates and is the direct responsibility of Subcommittee C09.60 onAnnual Book of A.STM Standards,Vol 04.02.Testing Fresh Concrete.3 For referenced ASTM standards,visit the ASTM website,www.astm.org,orCurrent edition approved Oct.1,2014.Published November 2014.Originallycontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMapproved in 1942.Last previous edition approved in 2014 as C172-14.DOI:Standards volume information.refer to the standards Document Summary page on10.1520/C0172C0172M-14A.the ASTM website.*A Summary of Changes section appears at the end of this standardCopyright ASTM Intemational,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesC172/C172M-14a5.Procedureinto one composite sample for test purposes.In any case do not5.1 Size of Sample-Make the samples to be used forobtain samples until after all of the water and any admixturesstrength tests a minimum of 28 L 1 ft.Smaller samples arehave been added to the mixer:also do not obtain samples fromnot prohibited for routine air content,temperature,and slumpthe very first or last portions of the batch discharge(Note 3).tests.The size of the samples shall be dictated by the maximumSample by repeatedly passing a receptacle through the entireaggregate sizedischarge stream or by completely diverting the discharge intoa sample container.Regulate the rate of discharge of the batch5.2 The procedures used in sampling shall include the use ofby the rate of revolution of the drum and not by the size of theevery precaution that will assist in obtaining samples that aregate opening.truly representative of the nature and condition of concrete5.2.4 Sampling from Continuous Mixers-Sample the con-sampled as follows:crete after the discharge of at least 140 L 5 ftof concrete,NorE 2-Sampling should normally be performed as the concrete isfollowing all mixture proportioning adjustments.Sample thedelivered from the mixer to the conveying vehicle used to transport theconcrete at the frequency specified by collecting two or moreconcrete to the forms;however,specifications may require other points ofportions taken at regularly spaced intervals during discharge ofsampling.such as the discharge of a concrete pump.the concrete.Take the portions so obtained within the time5.2.1 Sampling from Stationary Mixers,Except Pavinglimit specified in Section 4,and combine them into oneMixers-Sample the concrete by collecting two or morecomposite sample for test purposes.Do not obtain samplesportions taken at regularly spaced intervals during discharge offrom the very first or last portions of a mixers continuousthe middle portion of the batch.Obtain these portions withindischarge(Note 3).Sample by repeatedly passing a receptaclethe time limit specified in Section 4.Combine into onethrough the entire discharge stream or by completely divertingcomposite sample for testing purposes.Do not obtain portionsthe discharge into a sample container.After obtaining theof the composite sample from the very first or last part of thecomposite sample,wait a minimum of 2 minutes and abatch discharge(Note 3).Perform sampling by passing amaximum of 5 minutes before beginning tests(Note 5).receptacle completely through the discharge stream,or bycompletely diverting the discharge into a sample container.IfNorE 5-The waiting period prior to commencing the testing is neededbecause the mix water is input only seconds before discharge from thedischarge of the concrete is too rapid to divert the completecontinuous mixer.discharge stream,discharge the concrete into a container ortransportation unit sufficiently large to accommodate the entire5.2.5 Sampling from Open-Top Truck Mixers,Agitators,Nonagitating Equipment,or Other Types of Open-Topbatch and then accomplish the sampling in the same manner asgiven above.Take care not to restrict the flow of concrete fromContainers-Take samples by whichever of the proceduresdescribed in 5.2.1,5.2.2,or 5.2.3 is most applicable under thethe mixer,container,or transportation unit so as to causegiven conditions.segregation.These requirements apply to both tilting andnontilting mixers.6.Additional Procedure for Large Maximum SizeNorE 3-No samples should be taken before 10 or after 90%of theAggregate Concretebatch has been discharged.Due to the difficulty of determining the actualquantity of concrete discharged,the intent is to provide samples that are6.1 When the concrete contains aggregate larger than thatrepresentative of widely separated portions,but not the beginning and theappropriate for the size of the molds or equipment to be used,end of the load.wet-sieve the sample as described below except perform5.2.2 Sampling from Paving Mixers-Sample the concretedensity(unit weight)tests for use in yield computations on theafter the contents of the paving mixer have been discharged.full mix.Obtain samples from at least five different portions of the pileNorE 6-The effect of wet-sieving on the test results should beand combine them into one composite sample for test purposes.considered.For example,wet-sieving concrete causes the loss of a smallAvoid contamination with subgrade material or prolongedamount of air due to additional handling.The air content of the wet-sievedcontact with and absorptive subgrade.To preclude contamina-fraction of concrete is greater than that of the total concrete because thetion or absorption by the subgrade,sample the concrete bylarger size aggregate which is removed does not contain air.The apparentstrength of wet-sieved concrete in smaller specimens is usually greaterplacing three shallow containers on the subgrade and discharg-than that of the total concrete in larger appropriate size specimens.Theing the concrete across the container.Combine the samples soeffect of these differences may need to be considered or determined byobtained into one composite sample for test purposes.Thesupplementary testing for quality control or test result evaluation pur-containers shall be of a size sufficient to provide a compositeposes.sample size that is in agreement with the maximum aggregate6.2 Definition:size.6.2.1 wet-sieving concrete-the process of removing aggre-NorE 4-In some instances,the containers may have to be supportedgate larger than a designated size from the fresh concrete byabove the subgrade to prevent displacement during discharge.sieving it on a sieve of the designated size.5.2.3 Sampling from Revolving Drum Truck Mixers or6.3 Apparatus:Agitafors-Sample the concrete by collecting two or more6.3.1 Sieves,as designated,conforming to Specificationportions taken at regularly spaced intervals during discharge ofE11.the middle portion of the batch.Take the samples so obtained6.3.2 Receptacle-A container of suitable size having awithin the time limit specified in Section 4 and combine themnonabsorbent surface.4C172/C172M-14a6.3.3 Wet-Sieving Equipment-Equipment for wet-sievingaggregate retained on the sieve shall not be wiped from itconcrete shall be a sieve as noted in 6.3.1 of suitable size andbefore it is discarded.Place only enough concrete on the sieveconveniently arranged and supported so that one can shake itat any one time so that after sieving,the thickness of the layerrapidly by either hand or mechanical means.Generally,aof retained aggregate is not more than one particle thick.Thehorizontal back and forth motion is preferred.The equipmentconcrete which passes the sieve shall fall into a batch pan ofshall be capable of rapidly and effectively removing thesuitable size which has been dampened before use or onto adesignated size of aggregate.clean,moist,nonabsorbent surface.Scrape any mortar adher-6.3.4 Hand Tools-Shovels,hand scoops,plasteringing to the sides of the wet-sieving equipment into the batch.trowels,and rubber gloves as required.After removing the larger aggregate particles by wet-sieving6.4 Procedure:remix the batch with a shovel the minimum amount necessary6.4.1 Wet-Sieving-After sampling the concrete,pass theto ensure uniformity and proceed testing immediately.concrete over the designated sieve and remove and discard theaggregate retained.This shall be done before remixing.Shake7.Keywordsor vibrate the sieve by hand or mechanical means until no7.1 air content;batch;composite sample;concrete;slump;undersize material remains on the sieve.Mortar adhering to thetemperature;wet-sievingSUMMARY OF CHANGESCommittee C09 has identified the location of selected changes to this practice since the last issue,C172-14,that may impact the use of this practice.(Approved October 1,2014)(/Revised first sentence of 5.2.4.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard.Users of this standard are expressly advised that determination of the validity of any such patent rights,and the riskof infringement of such rights,are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised,either reapproved or withdrawn.Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM Intemational Headquarters.Your comments will receive careful consideration at a meeting of theresponsible technical committee,which you may attend.If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards,at the address shown below.This standard is copyrighted by ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,United States.Individual reprints(single or multiple copies)of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585(phone),610-832-9555(fax),or serviceastm.org(e-mail);or through the ASTM website(www.astm.org).Permission rights to photocopy the standard may also be secured from the Copyright Clearance Center,222Rosewood Drive,Danvers,MA 01923.Tel:(978)646-2600:http:/ ASTM International