|This article does not cite any references or sources. (December 2009)|
Aggregate base is typically composed of crushed rock capable of passing through a 3⁄4 in (19.05 mm) rock screen. The component particles will vary in size from 3/4 inch down to dust. The material can be made of virgin (newly mined) rock, or of recycled asphalt and concrete.
"Base course" refers to the sub-base layer of an asphalt roadway. Generally consisting of larger grade aggregate, spread and compacted to provide a stable base for further layers of aggregates or asphalt pavement. Aggregate base course is often referred to as ABC.