AASHTO R 60-2012 Standard Practice for Sampling Freshly Mixed Concrete.pdf
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1、Standard Practice for Sampling Freshly Mixed Concrete AASHTO Designation: R 60-12 (2016) Release: Group 1 (April 2016) ASTM Designation: C172-10 American Association of State Highway and Transportation Officials 444 North Capitol Street N.W., Suite 249 Washington, D.C. 20001 TS-3b R 60-1 AASHTO Stan
2、dard Practice for Sampling Freshly Mixed Concrete AASHTO Designation: R 60-12 (2016) Release: Group 1 (April 2016) ASTM Designation: C172-10 1. SCOPE 1.1. This method covers the procedures for obtaining representative samples of fresh concrete as delivered to the project site and on which tests are
3、to be performed to determine compliance with quality requirements of the specifications under which the concrete is furnished (Note 1). The method includes sampling from stationary, paving, and truck mixers and from agitating and nonagitating equipment used to transport central mixed concrete. 1.2.
4、The values stated in SI units are to be regarded as the standard. The inch-pound equivalents of metric units may be approximate. Note 1Combined samples are required by this method, unless specifically excepted by procedures governing the tests to be performed, such as tests to determine uniformity o
5、f consistency and mixer efficiency. Procedures used to select the specific test batches are not described in this method, but it is recommended that random sampling be used to determine overall specification compliance. 1.3. This practice also covers the procedures to be used for preparing a sample
6、of concrete for further testing where it is desirable or necessary to remove the aggregate larger than a designated size. This removal of larger aggregate particles is preferably accomplished by wet-sieving. 1.4. The text of this standard references notes and footnotes that provide explanatory mater
7、ial and shall not be considered as requirements of the practice. 1.5. This standard does not purport to address of all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the
8、 applicability of regulatory limitations prior to use. WarningFresh hydraulic cementitious mixtures are caustic and may cause chemical burns to skin and tissue upon prolonged exposure. 2. REFERENCED DOCUMENT 2.1. AASHTO Standard: M 92, Wire-Cloth Sieves for Testing Purposes 3. SIGNIFICANCE AND USE 3
9、.1. This practice is intended to provide standard requirements and procedures for sampling freshly mixed concrete from different containers used in the production or transportation of concrete. The detailed requirements as to materials, mixtures, air content, temperature, number of specimens, slump,
10、 interpretation of results, and precision and bias are described in specific test methods. 2016 by the American Association of State Highway and Transportation Officials.All rights reserved. Duplication is a violation of applicable law.TS-3b R 60-2 AASHTO 4. SAMPLING 4.1. The elapsed time shall not
11、exceed 15 min between obtaining the first and final portions of the composite sample. 4.1.1. Transport the individual samples to the place where fresh concrete tests are to be performed or where test specimens are to be molded. They shall then be combined and remixed with a shovel in the minimum amo
12、unt necessary to ensure uniformity and compliance with the minimum time limits specified in Section 4.1.2. 4.1.2. Start tests for slump, temperatures, and air content within 5 min after obtaining the final portion of the composite sample. Complete these tests quickly. Start molding specimens for str
13、ength tests within 15 min after fabricating the composite sample. Quickly obtain and use the sample and protect the sample from the sun, wind, and other sources of rapid evaporation and from contamination. 5. PROCEDURE 5.1. Size of SampleMake the samples to be used for strength tests a minimum of 28
14、 L (1 ft3). Smaller samples are not prohibited for routine air content and slump tests and the size shall be dictated by the maximum aggregate size. 5.2. The procedures used in sampling shall include the use of every precaution that will assist in obtaining samples that are truly representative of t
15、he nature and condition of concrete sampled as follows: Note 2Sampling should normally be performed as the concrete is delivered from the mixer to the conveying vehicle used to transport the concrete to the forms; however, specifications may require other points of sampling, such as at the discharge
16、 of a concrete pump. 5.2.1. Note 3As routine air content and slump tests are not readily adaptable to sampling the concrete at two or more regularly spaced intervals during discharge of the middle portion of the batch as specified in this method, the sample for air content, slump, and temperature ma
17、y be taken after at least 0.20 m3(0.25 yd3) of concrete has been discharged. 5.2.2. Sampling from Stationary Mixers, Except Paving MixersSample the concrete by collecting two or more portions taken at regularly spaced intervals during discharge of the middle of the batch. Obtain these portions withi
18、n the time limit specified in Section 4. Combine the portions into one sample for testing purposes. Do not obtain portions of the composite sample from the very first or last part of the batch discharge (Note 4). Perform sampling by passing a receptacle completely through the discharge stream or by
19、completely diverting the discharge into a sample container. If discharge of the concrete is too rapid to divert the complete discharge stream, discharge the concrete into a container or transportation unit sufficiently large to accommodate the entire batch and then accomplish the sampling in the sam
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