1.1This specification pertains to admixtures for masonry mortars. Admixtures are substances other than Specification C270 prescribed materials of water, aggregate, and cementitious materials that are used to improve one or more of the recognized desirable properties of conventional masonry mortar.

1.2This specification does not cover coloring pigments.

Note 1:Information on coloring pigments can be found in Specification C979/C979M.

1.3This specification does not cover additives that are added to the cementitious materials during the manufacture of the cementitious materials.

1.4Acceptance of an admixture is based on its performance in an admixed mortar. Acceptance of the admixed masonry mortar is based on attainment of performance either equivalent to that required for conventional mortar or improved performance of one or more indicated properties, while maintaining required performance levels for other properties.

1.5The text of this standard refers to notes and footnotes that provide explanatory material. These notes and footnotes (excluding those in tables and figures) shall not be considered as requirements of the standard.

1.6The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.

Note 2:The testing laboratory performing the test methods referenced in this specification should be evaluated in accordance with Practice C1093.

1.7This 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.