ASTM C638-14

1.1 This descriptive nomenclature is intended to give accurate descriptions of some common or important naturally occurring and synthetic constituents of aggregates for radiation-shielding concrete, that, at the same time, are not common or important constituents of concrete aggregates in general use. While most of the minerals and rocks discussed below may occur in small quantities in aggregates in general use, they are not major constituents of such aggregates. Common constituents of aggregates in general use are described in Descriptive Nomenclature C294. Radiation-shielding concrete often contains such aggregates, but other special aggregates are used in some circumstances.