1.1 This specification covers hollow and solid (see and ) 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: (1) normal weight, (2) medium weight, and (3) lightweight. These units are suitable for both loadbearing and nonloadbearing applications.1.2 Concrete masonry units covered by this specification are made from lightweight or normal weight aggregates,