Specific Gravity Testing

Measurement of the bulk specific gravity of asphalt is used primarily for quality control evaluation of bituminous mixes. Specific gravity is defined as the ratio of the mass of a given material to that of an equal volume of water at the same reference temperature.

In material testing the three most common forms of specific gravity are: specific gravity of solids, apparent specific gravity and bulk specific gravity.

Specific gravity of solids is generally applied to soil and considers only the solid fraction as if the voids of fluid or gas were not present. Apparent specific gravity includes in the measurement any voids within a solid material, such as aggregate. Bulk specific gravity includes both voids within individual particles as well as voids between the particles, such as a compacted asphalt mix sample.