Base course

Base Course in pavements refers to the sub-layer material of an asphalt roadway and is placed directly on top of the undisturbed soil so as to provide a foundation to support the top layer(s) of the pavement. Generally consisting of a specific type of construction aggregate, it is placed by means of attentive spreading and compacting to a minimum of 95% relative compaction, thus providing the stable foundation needed to support either additional layers of aggregates or the placement of asphalt concrete which is applied directly on top of an asphalt sealed Base Course. All resulting in a roadway pavement.

Aggregate Base (AB) is typically made of a recipe of mixing different sizes of crushed rock together forming the Aggregate which has certain desirable properties. "3/4 inch Aggregate Base, Class 2", is used in roadways and is an aggregate made of a specific recipe of different sizes and quality of rock inclusive of 3/4 inch to fine dust. 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.

Aggregate Base is used as the base course under asphalt concrete pavement roadways, under portland cement concrete slabs and structural foundations, and as backfill material for underground pipelines and other underground utilities within a roadway.

Aggregate Base Course is often referred simply as AB.


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  • Base course — Base Base, n. [F. base, L. basis, fr. Gr. ba sis a stepping, step, a base, pedestal, fr. bai nein to go, step, akin to E. come. Cf. {Basis}, and see {Come}.] 1. The bottom of anything, considered as its support, or that on which something rests… …   The Collaborative International Dictionary of English

  • base course — The layer(s) of a specified material of designed thickness placed on a sub base or subgrade to support the surface course. The base course and subgrade are structural elements of the pavement. In conjunction with the overlying asphalt surface,… …   Aviation dictionary

  • base course — noun Etymology: base (III) 1. a. : the first or lowest course of a wall (as of a foundation wall or of the wall of a building above the basement) b. : the bottom layer of material laid down in the construction of a pavement …   Useful english dictionary

  • base course material — noun material used as a foundation, as for a road, before the finishing or sealing surface is applied …   Australian English dictionary

  • Base — Base, n. [F. base, L. basis, fr. Gr. ba sis a stepping, step, a base, pedestal, fr. bai nein to go, step, akin to E. come. Cf. {Basis}, and see {Come}.] 1. The bottom of anything, considered as its support, or that on which something rests for… …   The Collaborative International Dictionary of English

  • Base hit — Base Base, n. [F. base, L. basis, fr. Gr. ba sis a stepping, step, a base, pedestal, fr. bai nein to go, step, akin to E. come. Cf. {Basis}, and see {Come}.] 1. The bottom of anything, considered as its support, or that on which something rests… …   The Collaborative International Dictionary of English

  • Base line — Base Base, n. [F. base, L. basis, fr. Gr. ba sis a stepping, step, a base, pedestal, fr. bai nein to go, step, akin to E. come. Cf. {Basis}, and see {Come}.] 1. The bottom of anything, considered as its support, or that on which something rests… …   The Collaborative International Dictionary of English

  • Base plate — Base Base, n. [F. base, L. basis, fr. Gr. ba sis a stepping, step, a base, pedestal, fr. bai nein to go, step, akin to E. come. Cf. {Basis}, and see {Come}.] 1. The bottom of anything, considered as its support, or that on which something rests… …   The Collaborative International Dictionary of English

  • Base ring — Base Base, n. [F. base, L. basis, fr. Gr. ba sis a stepping, step, a base, pedestal, fr. bai nein to go, step, akin to E. come. Cf. {Basis}, and see {Come}.] 1. The bottom of anything, considered as its support, or that on which something rests… …   The Collaborative International Dictionary of English

  • base — i. A location where aircraft with all facilities are based. Refers to an air force base, naval air station, and fixed base operator. ii. In air traffic control phraseology and when transmitted on the radio, it means turning onto the base leg of… …   Aviation dictionary


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