Bulk specific gravity is the determination of the specific gravity including permeable and impermeable air voids or pores that exist within the aggregate.

• A. True
• B. False
• C. Depends on sample size
• D. Only for air-dried samples

Answer: (A)

Bulk specific gravity measures the density of aggregate based on its whole particle volume, including all internal air voids. In practice, you determine it with a saturated surface-dry method so that water can fill open (permeable) pores while closed (impermeable) pores remain air-filled. This means the volume considered includes those internal voids, so the bulk specific gravity is lower than the apparent solid-material gravity because the pores reduce the overall density. This value is used for calculating compaction voids and binder content in asphalt mixes, making the statement true.