This specification covers hollow and solid concrete masonry units made from hydraulic cement, water, and mineral aggregates with or without the inclusion of other materials. There are three classes of concrete masonry units: normal weight, medium weight, and lightweight. These units are suitable for both loadbearing and nonloadbearing applications. Concrete masonry units shall be made from lightweight or normal weight aggregates, or both. This abstract is a brief summary of the referenced standard. It is informational only and not an official part of the standard; the full text of the standard itself must be referred to for its use and application. ASTM does not give any warranty express or implied or make any representation that the contents of this abstract are accurate, complete or up to date.