ASTM C172C172M-17 Standard Practice for Sampling Freshly Mixed Concrete.pdf

1、Designation: C172/C172M 17Standard 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 p

2、arentheses indicates the year of last reapproval.A superscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This practice covers procedures for obtaining represen-tative samples of fresh concrete as delivered to the project siteon which tests are to be

3、performed to determine compliancewith quality requirements of the specifications under which theconcrete is furnished (Note 1). The practice includes samplingfrom stationary, paving and truck mixers, and from agitatingand nonagitating equipment used to transport central-mixedconcrete and from contin

4、uous mixing equipment as describedin Specification C685/C685M.1.2 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard. The values stated ineach system may not be exact equivalents; therefore, eachsystem shall be used independently of the other. Combining

5、values from the two systems may result in non-conformancewith the standard.NOTE 1Composite samples are required by this practice, unlessspecifically excepted by procedures governing the tests to be performedsuch as tests to determine uniformity of consistency and mixer efficiency.Procedures used to

6、select the specific test batches are not described in thispractice, but it is recommended that random sampling be used todetermine overall specification compliance.1.3 This practice also covers the procedures to be used forpreparing a sample of concrete for further testing where it isdesirable or ne

7、cessary to remove the aggregate larger than adesignated size. This removal of larger aggregate particles ispreferably accomplished by wet-sieving.1.4 The text of this standard references notes and footnoteswhich provide explanatory material and shall not be consideredas requirements of the practice.

8、1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use

9、.(WarningFresh hydraulic cementitious mixtures are causticand may cause chemical burns to skin and tissue uponprolonged exposure.2)1.6 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for

10、 theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:3C685/C685M Specification for Concrete Made by Volumet-ric Batching and Continuous MixingE11 Specificati

11、on for Woven Wire Test Sieve Cloth and TestSieves3. Significance and Use3.1 This practice is intended to provide standard require-ments and procedures for sampling freshly mixed concretefrom different containers used in the production or transporta-tion of concrete. The detailed requirements as to m

12、aterials,mixtures, air content, temperature, number of specimens,slump, interpretation of results, and precision and bias are inspecific test methods.4. Sampling4.1 The elapsed time shall not exceed 15 min. betweenobtaining the first and final portions of the composite sample.4.1.1 Transport the ind

13、ividual samples to the place wherefresh concrete tests are to be performed or where test speci-mens are to be molded. They shall be combined and remixedwith a shovel the minimum amount necessary to ensureuniformity and compliance with the maximum time limitsspecified in 4.1.2.4.1.2 Start tests for s

14、lump, temperature, and air contentwithin 5 min after obtaining the final portion of the compositesample. Complete these tests expeditiously. Start molding1This practice is under the jurisdiction of ASTM Committee C09 on Concreteand ConcreteAggregates and is the direct responsibility of Subcommittee

15、C09.60 onTesting Fresh Concrete.Current edition approved Oct. 1, 2017. Published October 2017. Originallyapproved in 1942. Last previous edition approved in 2014 as C172/C172M14a.DOI: 10.1520/C0172_C0172M-17.2Section on Safety Precautions, Manual of Aggregate and Concrete Testing,Annual Book of ASTM

16、 Standards, Vol 04.02.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.*A Summary of Changes section appears a

17、t the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles f

18、or theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1specimens for strength tests within 15 min after fabricating thecomposite sample. Expeditiously obtain and use the sampleand protect the sample

19、 from the sun, wind, and other sources ofrapid evaporation, and from contamination.5. Procedure5.1 Size of SampleMake the samples to be used forstrength tests a minimum of 28 L 1 ft3. Smaller samples arenot prohibited for routine air content, temperature, and slumptests. The size of the samples shal

20、l be dictated by the maximumaggregate size.5.2 The procedures used in sampling shall include the use ofevery precaution that will assist in obtaining samples that aretruly representative of the nature and condition of concretesampled as follows:NOTE 2Sampling should normally be performed as the conc

21、rete isdelivered from the mixer to the conveying vehicle used to transport theconcrete to the forms; however, specifications may require other points ofsampling, such as the discharge of a concrete pump.5.2.1 Sampling from Stationary Mixers, Except PavingMixersSample the concrete by collecting two o

22、r moreportions taken at regularly spaced intervals during discharge ofthe middle portion of the batch. Obtain these portions withinthe time limit specified in Section 4. Combine into onecomposite sample for testing purposes. Do not obtain portionsof the composite sample from the very first or last p

23、art of thebatch discharge (Note 3). Perform sampling by passing areceptacle completely through the discharge stream, or bycompletely diverting the discharge into a sample container. Ifdischarge of the concrete is too rapid to divert the completedischarge stream, discharge the concrete into a contain

24、er ortransportation unit sufficiently large to accommodate the entirebatch and then accomplish the sampling in the same manner asgiven above. Take care not to restrict the flow of concrete fromthe mixer, container, or transportation unit so as to causesegregation. These requirements apply to both ti

25、lting andnontilting mixers.NOTE 3No samples should be taken before 10 % or after 90 % of thebatch has been discharged. Due to the difficulty of determining the actualquantity of concrete discharged, the intent is to provide samples that arerepresentative of widely separated portions, but not the beg

26、inning and theend of the load.5.2.2 Sampling from Paving MixersSample the concreteafter the contents of the paving mixer have been discharged.Obtain samples from at least five different portions of the pileand combine them into one composite sample for test purposes.Avoid contamination with subgrade

27、 material or prolongedcontact with and absorptive subgrade.NOTE 4Discharging concrete across shallow containers placed on thesubgrade, or supported above the subgrade, may be effective in precludingcontamination or absorption by the subgrade. If used, the concrete fromthe shallow containers should p

28、rovide a composite sample that is inagreement with the maximum aggregate size.5.2.3 Sampling from Revolving Drum Truck Mixers orAgitatorsSample the concrete by collecting two or moreportions taken at regularly spaced intervals during discharge ofthe middle portion of the batch. Take the samples so o

29、btainedwithin the time limit specified in Section 4 and combine theminto one composite sample for test purposes. In any case do notobtain samples until after all of the water and any admixtureshave been added to the mixer; also do not obtain samples fromthe very first or last portions of the batch d

30、ischarge (Note 3).Sample by repeatedly passing a receptacle through the entiredischarge stream or by completely diverting the discharge intoa sample container. Regulate the rate of discharge of the batchby the rate of revolution of the drum and not by the size of thegate opening.5.2.4 Sampling from

31、Continuous MixersSample the con-crete after the discharge of at least 140 L 5 ft3 of concrete,following all mixture proportioning adjustments. Sample theconcrete at the frequency specified by collecting two or moreportions taken at regularly spaced intervals during discharge ofthe concrete. Take the

32、 portions so obtained within the timelimit specified in Section 4, and combine them into onecomposite sample for test purposes. Do not obtain samplesfrom the very first or last portions of a mixers continuousdischarge (Note 3). Sample by repeatedly passing a receptaclethrough the entire discharge st

33、ream or by completely divertingthe discharge into a sample container. After obtaining thecomposite sample, wait a minimum of 2 minutes and amaximum of 5 minutes before beginning tests (Note 5).NOTE 5The waiting period prior to commencing the testing is neededbecause the mix water is input only secon

34、ds before discharge from thecontinuous mixer.5.2.5 Sampling from Open-Top Truck Mixers, Agitators,Nonagitating Equipment, or Other Types of Open-TopContainersTake samples by whichever of the proceduresdescribed in 5.2.1, 5.2.2,or5.2.3 is most applicable under thegiven conditions.6. Additional Proced

35、ure for Large Maximum SizeAggregate Concrete6.1 When the concrete contains aggregate larger than thatappropriate for the size of the molds or equipment to be used,wet-sieve the sample as described below except performdensity (unit weight) tests for use in yield computations on thefull mix.NOTE 6The

36、effect of wet-sieving on the test results should beconsidered. For example, wet-sieving concrete causes the loss of a smallamount of air due to additional handling. The air content of the wet-sievedfraction of concrete is greater than that of the total concrete because thelarger size aggregate which

37、 is removed does not contain air. The apparentstrength of wet-sieved concrete in smaller specimens is usually greaterthan that of the total concrete in larger appropriate size specimens. Theeffect of these differences may need to be considered or determined bysupplementary testing for quality contro

38、l or test result evaluation pur-poses.6.2 Definition:6.2.1 wet-sieving concretethe process of removing aggre-gate larger than a designated size from the fresh concrete bysieving it on a sieve of the designated size.6.3 Apparatus:6.3.1 Sieves, as designated, conforming to SpecificationE11.6.3.2 Recep

39、tacleA container of suitable size having anonabsorbent surface.C172/C172M 1726.3.3 Wet-Sieving EquipmentEquipment for wet-sievingconcrete shall be a sieve as noted in 6.3.1 of suitable size andconveniently arranged and supported so that one can shake itrapidly by either hand or mechanical means. Gen

40、erally, ahorizontal back and forth motion is preferred. The equipmentshall be capable of rapidly and effectively removing thedesignated size of aggregate.6.3.4 Hand ToolsShovels, hand scoops, plasteringtrowels, and rubber gloves as required.6.4 Procedure:6.4.1 Wet-SievingAfter sampling the concrete,

41、 pass theconcrete over the designated sieve and remove and discard theaggregate retained. This shall be done before remixing. Shakeor vibrate the sieve by hand or mechanical means until noundersize material remains on the sieve. Mortar adhering to theaggregate retained on the sieve shall not be wipe

42、d from itbefore it is discarded. Place only enough concrete on the sieveat any one time so that after sieving, the thickness of the layerof retained aggregate is not more than one particle thick. Theconcrete which passes the sieve shall fall into a batch pan ofsuitable size which has been dampened b

43、efore use or onto aclean, moist, nonabsorbent surface. Scrape any mortar adher-ing to the sides of the wet-sieving equipment into the batch.After removing the larger aggregate particles by wet-sievingremix the batch with a shovel the minimum amount necessaryto ensure uniformity and proceed testing i

44、mmediately.7. Keywords7.1 air content; batch; composite sample; concrete; slump;temperature; wet-sievingSUMMARY OF CHANGESCommittee C09 has identified the location of selected changes to this practice since the last issue,C172/C172M14a, that may impact the use of this practice. (Approved October 1,

45、2017)(1) Revised 5.2.2. (2) Revised Note 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

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