Standard Active Last Updated: Feb 27, 2024 Track Document
ASTM C311/C311M-24

Standard Test Methods for Sampling and Testing Coal Ash or Natural Pozzolans for Use in Concrete

Standard Test Methods for Sampling and Testing Coal Ash or Natural Pozzolans for Use in Concrete C0311_C0311M-24 ASTM|C0311_C0311M-24|en-US Standard Test Methods for Sampling and Testing Coal Ash or Natural Pozzolans for Use in Concrete Standard new BOS Vol. 04.02 Committee C09
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Significance and Use

4.1 These test methods are used to develop data for comparison with the requirements of Specification C618 or Specification C1697. These test methods are based on standardized testing in the laboratory and are not intended to simulate job conditions.

4.1.1 Strength Activity Index—The test for strength activity index is used to determine whether coal ash or natural pozzolan results in an acceptable level of strength development when used in concrete. Since the test is performed with mortar, the results may not provide a direct correlation of how the coal ash or natural pozzolan will contribute to strength in concrete.

4.1.2 Chemical Tests—The chemical component determinations and the limits placed on each do not predict the performance of a coal ash or natural pozzolan in concrete, but collectively help describe composition and uniformity of the material.


1.1 These test methods cover procedures for sampling and testing coal ash and raw or calcined pozzolans for use in concrete.

1.2 The procedures appear in the following order:












Reagents and apparatus




Moisture content

11 and 12



Loss on ignition

13 and 14



Silicon dioxide, aluminum oxide, iron oxide,
calcium oxide, magnesium oxide, sulfur
trioxide, sodium oxide and potassium




Available alkali

16 and 17


















Increase of drying shrinkage of mortar bars

21 – 23







Air-entrainment of mortar

25 and 26



Strength activity index

27 – 30



Water requirement




Effectiveness of Coal Ash or Natural Pozzolan in
Controlling Alkali-Silica Reactions




Effectiveness of Coal Ash or Natural Pozzolan in
Contributing to Sulfate Resistance


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 are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.

Note 1: Sieve size is identified by its standard designation in Specification E11. The alternative designation given in parentheses is for information only and does not represent a different standard sieve size.

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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.5 The text of this standard references notes and footnotes that provide explanatory information. These notes and footnotes (excluding those in tables) shall not be considered as requirements of this standard.

1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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Book of Standards Volume: 04.02
Developed by Subcommittee: C09.24
Pages: 11
DOI: 10.1520/C0311_C0311M-24
ICS Code: 91.100.30