ASTM D7172-06

Bulk relative density (specific gravity) is the characteristic generally used for calculation of the volume occupied by the aggregate in various mixtures containing aggregate including Portland cement concrete, bituminous concrete, and other mixtures that are proportioned or analyzed on an absolute volume basis. Bulk relative density (specific gravity) is used in the computation of voids in aggregate in C 1252 and C 29/ C 29M. Bulk relative density (specific gravity) determined on the saturated surface dry (SSD) basis is used if the aggregate is wet, that is, if its absorption has been satisfied. Conversely, the bulk relative density (specific gravity) determined on the oven-dry basis is used for computations when the aggregate is dry or assumed to be dry.

Apparent relative density (specific gravity) pertains to the relative density of the solid material making up the constituent particles not including the pore space within the    particles that is accessible to water. This value is not widely used in construction    aggregate technology.

Water absorption values are used to calculate the change in the mass of an    aggregate due to water absorbed in the pore spaces within the constituent    particles, compared to the dry condition, when it is deemed that the aggregate    has been in contact with water long enough to satisfy most of the absorption    potential. The laboratory standard for absorption is that obtained after    submerging dry aggregate for approximately 24 hours in water. Aggregates    mined from below the water table may have a higher absorption when used, if not allowed to dry. Conversely, some aggregates when used may contain an    amount of absorbed moisture less than the 24 hours soaked condition: For an aggregate that has been in contact with water and that had free moisture on the    particle surface, the percentage of free moisture can be determined by deducting    the absorption from the total moisture content determined according to C 566 by drying.

1.1 This test method covers the determination of the relative density (specific gravity) and absorption of fine aggregates.

1.2 The values stated in SI units are to be regarded as the standard.

1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.