Coarse aggregate retained on the 4.75-mm (No. 4) sieve shall consist of durable particles of crushed stone, gravel, or slag. At least 75% of the particles retained on a 9.5-mm [3⁄8-in.] sieve shall have two or more fractured faces.
AASHTO Soil Classification
Materials for Aggregate and Soil–Aggregate Subbase, Base, and Surface Courses