Aggregate base

Aggregate base is a construction aggregate typically composed of crushed rock capable of passing through a rock screen. The component particles will vary in size from 20 mm down to dust. The material can be made of virgin (newly mined) rock, or of recycled asphalt and concrete. Base is used as a

base course The base course or basecourse in pavements is a layer of material in an asphalt roadway, race track, riding arena, or sporting field. It is located under the surface layer consisting of the ''wearing course'' and sometimes an extra ''binder cour ...

road A road is a linear way for the conveyance of traffic that mostly has an improved surface for use by vehicles (motorized and non-motorized) and pedestrians. Unlike streets, the main function of roads is transportation. There are many types of ...

ways, as a base course for cement pads and foundations, and as backfill material for underground pipelines and other underground utilities. "

Base course The base course or basecourse in pavements is a layer of material in an asphalt roadway, race track, riding arena, or sporting field. It is located under the surface layer consisting of the ''wearing course'' and sometimes an extra ''binder cour ...

" refers to the sub-base layer of an

asphalt Asphalt, also known as bitumen (, ), is a sticky, black, highly viscous liquid or semi-solid form of petroleum. It may be found in natural deposits or may be a refined product, and is classed as a pitch. Before the 20th century, the term ...

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. Pavement engineering Pavements {{civil-engineering-stub