ASTM C172-2008 Standard Practice for Sampling Freshly Mixed Concrete《新搅拌混凝土取样标准实施规程》.pdf
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1、Designation: C 172 08Standard Practice forSampling Freshly Mixed Concrete1This standard is issued under the fixed designation C 172; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses
2、 indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope*1.1 This practice covers procedures for obtaining represen-tative samples of f
3、resh concrete as delivered to the project siteon which tests are to be 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 nonagit
4、ating equipment used to transport central-mixedconcrete.1.2 The values stated in SI units are to be regarded asstandard. The values given in parentheses are mathematicalconversions to inch-pound units that are provided for informa-tion only and are not considered standard.NOTE 1Composite samples are
5、 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 select the specific test batches are not described in thispractice, but it is recommended that random
6、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 necessary to remove the aggregate larger than adesignated size. This removal of larger aggregate particl
7、es 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.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its u
8、se. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. (WarningFreshhydraulic cementitious mixtures are caustic and may causechemical burns to skin and tissue upon prolong
9、ed exposure.2)2. Referenced Documents2.1 ASTM Standards:3E11 Specification for Wire Cloth and Sieves for TestingPurposes3. 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 produ
10、ction or transporta-tion of concrete. The detailed requirements as to materials,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 f
11、irst and final portions of the composite sample.4.1.1 Transport the individual 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
12、 with the maximum time limitsspecified in 4.1.2.4.1.2 Start tests for slump, temperature, and air contentwithin 5 min after obtaining the final portion of the compositesample. Complete these tests expeditiously. Start moldingspecimens for strength tests within 15 min after fabricating thecomposite s
13、ample. Expeditiously obtain and use the sampleand protect the sample 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
14、air content, temperature, and slumptests. The size of the samples shall be dictated by the maximumaggregate size.1This practice is under the jurisdiction of ASTM Committee C09 on Concreteand ConcreteAggregates and is the direct responsibility of Subcommittee C09.60 onTesting Fresh Concrete.Current e
15、dition approved June 1, 2008. Published July 2008. Originally approvedin 1942. Last previous edition approved in 2007 as C 172 07a.2Section on Safety Precautions, Manual of Aggregate and Concrete Testing,Annual Book of ASTM Standards, Vol 04.02.3For referenced ASTM standards, visit the ASTM website,
16、 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.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Dri
17、ve, PO Box C700, West Conshohocken, PA 19428-2959, United States.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
18、 performed as the concrete 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 concre
19、te by collecting two or 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 th
20、e very first or last part 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 c
21、oncrete into a container 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 require
22、ments apply to both tilting 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 por
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