ASTM C311 – Standard Test Methods for Sampling and Testing Coal Ash or Natural Pozzolans for Use in Concrete
Description:
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.
Scope
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:
| Sections | |
| Sampling | 7 |
| CHEMICAL ANALYSIS | |
| Reagents and apparatus | 10 |
| 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 oxide | 15 |
| Available alkali | 16 and 17 |
| Ammonia | 18 |
| PHYSICAL TESTS | |
| Density | 19 |
| Fineness | 20 |
| Increase of drying shrinkage of mortar bars | 21 – 23 |
| Soundness | 24 |
| Air-entrainment of mortar | 25 and 26 |
| Strength activity index | 27 – 30 |
| Water requirement | 31 |
| Effectiveness of Coal Ash or Natural Pozzolan in Controlling Alkali-Silica Reactions | 32 |
| Effectiveness of Coal Ash or Natural Pozzolan in Contributing to Sulfate Resistance | 34 |
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.
ASTM C31