ASTM C31/C31M-08a

This practice provides standardized requirements for making, curing, protecting, and transporting concrete test specimens under field conditions.

If the specimens are made and standard cured, as stipulated herein, the resulting strength test data when the specimens are tested are able to be used for the following purposes:

Acceptance testing for specified strength,

Checking adequacy of mixture proportions for strength, and

Quality control.

If the specimens are made and field cured, as stipulated herein, the resulting strength test data when the specimens are tested are able to be used for the following purposes:

Determination of whether a structure is capable of being put in service,

Comparison with test results of standard cured specimens or with test results from various in-place test methods,

Adequacy of curing and protection of concrete in the structure, or

Form or shoring removal time requirements.

1.1 This practice covers procedures for making and curing cylinder and beam specimens from representative samples of fresh concrete for a construction project.

1.2 The concrete used to make the molded specimens shall be sampled after all on-site adjustments have been made to the mixture proportions, including the addition of mix water and admixtures. This practice is not satisfactory for making specimens from concrete not having measurable slump or requiring other sizes or shapes of specimens.

1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard. The SI units are shown in brackets.

1.4 This standard does not purport to address 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 applicability of regulatory limitations prior to use. (Warning—Fresh hydraulic cementitious mixtures are caustic and may cause chemical burns to exposed skin and tissue upon prolonged exposure. )

1.5 The text of this standard references notes which provide explanatory material. These notes shall not be considered as requirements of the standard.