ASTM C140/C140M-21 pdf free download.Standard Test Methods for Sampling and Testing Concrete Masonry Units and Related Units.
1.1 These test methods provide various testing procedures commonly used for evaluating characteristics of concrete masonry units and related concrete units. Methods are provided for sampling, measurement of dimensions, compressive strength. absorption, unit weight (density), moisture content, flexural load, and ballast weight. Not all methods are applicable to all unit types. however.
1.2 Specific testing and reporting procedures are included in annexes to these test methods for the following specifIc unit types:
4. Significance and Use
4.1 These test methods provide general testing requirements for application to a broad range of concrete products. Those general testing requirements are included in the body of this standard.
Nom 2—Consult manufacturer, supplier, product specifications, or other resources for more specific measurement or testing guidelines for those products not addressed with the annex of this standard.
4.2 These test methods provide specific testing requirements in two distinci sections. the requirements applicable to all units covered by these test methods and those applicable to the specific unit types. The requirements applicable to all units are included in the body of these test methods and those applicable to the specific unit types are included within the annexes.
5. Sampling
5. 1 Selection of Test Specimens.
5.1.1 For purposes of testing. full-sized units shall be selected by the purchaser or authorized representative. The selected specimens shall be of similar configuration and dimensions. Specimens shall be representative of the whole lot of units from which they arc selected.
5.2 Ni.,,nber of Specimens:
5.2.1 Unless specified otherwise in the applicable annex, a set of units shall consist of six full-size units.
5.3 Remove loose material from the specimens (including the cores) prior to determining the received weight.
NOTE 3—An abrasive stone or wire brush is typically used to remove loose material.
5.4 Identification—Mark each specimen so that it may be identified at any time. Markings shall cover not more than 5 % of the surface area of the specimen.
5.5 Received Weight—Prior to performing tests, weigh each specimen after sampling and marking.
Note 4—Received weights often have direct relationships with other unit properties and are therefore a useful method of evaluating results or for sorting purposes. It is good laboratory practice to separate sampled units for strength and absorption testing by received weight. such that the averages of the subsets of specimens are similar and representative of the sampled units. Received weight may also be useful in evaluating inconsistency in test results or unit production issues. The weight of a concrete masonry unit and related unit changes with time and exposure conditions. primarily as a result of the moisture within the unit. Therefore, to understand the context of a received weight value, it is also important to understand the point in time and the frame of reference when that weight was determined. "Time and place” should not refer to when and where the unit was sampled hut when and where the received weights were determined. In addition to date and time references, it is also important to know if those weights were determined after units reached equilibrium with lab environment, or before units were shipped. or after delivery to the job site, and so forth. Moisture content is flot a physical property requirement of concrete masonry units, therefore field measurement of received weight is not necessary (unless specifically specified for a particular job).