This specification covers lightweight aggregates intended for use in concrete masonry units when a prime consideration is to reduce the density of the units. Three general types of lightweight aggregates are covered by this specification: aggregates prepared by expanding, palletizing, or sintering products such as blast-furnace slag, clay, diatomite, fly ash, shale, or slate; aggregates prepared by processing natural materials such as pumice, scoria, or tuff; and aggregates consisting of end products of coal or coke combustion. The aggregates shall be composed predominately of lightweight-cellular and granular inorganic material. The aggregates shall not contain excessive amounts of deleterious substances, as determined by organic impurities, staining, and loss on ignition tests. Lightweight aggregate under test shall meet requirements for clay lumps and friable particles, uniformity of grading, loose bulk density, uniformity of loose bulk density, popouts, resistance to freezing and thawing, and drying shrinkage.

1.1 This specification covers lightweight aggregates intended for use in concrete masonry units when a prime consideration is to reduce the density of the units.

1.2 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. Some values have only SI units because the inch-pound equivalents are not used in practice.

1.3 The text of this specification references notes and footnotes which provide explanatory material. These notes and footnotes (excluding those in tables and figures) shall not be considered as requirements of the standard.