Base course
layer of material in asphalt roadways
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 course.
If there is a sub-base course, the base course is constructed directly above this layer. Otherwise, it is built directly on top of the subgrade. Typical base course thickness ranges from 100 to 150 millimetres (4 to 6 in) and is governed by underlying layer properties. Generally made of a construction aggregate, it is spread and compacted to at least 95% relative compaction, thus providing a stable foundation for additional layers of material.
Aggregate base (AB) is typically a mix of different sizes of crushed rock 20 mm or 3⁄4 in Aggregate Base, Class 2, is used in roadways and consists of rock particles of size 20 mm (3⁄4 in) and less. An aggregate is normally made from newly quarried rock, or it is sometimes allowed to be made from recycled asphalt concrete and/or Portland cement concrete.
Begin with the source’s own compact description: “Base course” is layer of material in asphalt roadways. The dossier treats that line as a proposition to test through Base, course and layer, not as a finished interpretation.
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Vocabulary and entity names are the principal evidence signals here, because they determine the precision of every later search. The source revision retrieved here is dated Jul 11, 2025. The linked authority identifier is Q2448067. None of the 0 selected statements returned an explicit reference.
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This entry incorporates text from “Base course” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.