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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.
The base course is the region of the pavement section that is located directly under the surface course. If there is a subbase course, the base course is constructed directly about this layer. Otherwise, it is built directly on top of the subgrade. Typical base course thickness ranges from 4 to 6 inches and is governed by underlying layer ...
If the final pavement is to have vehicle traffic, a layer of subbase of crushed stone or concrete must come next—this layer will even out the subgrade and will bear the heaviest load from the pavement above. Next comes the base course (also called the aggregate base course or ABC) composed of crushed gravel varying from 0.75 in (1.9 cm) down ...
This book covers the functional design of roads and highways including such things as the layout of intersections, horizontal curves, and vertical curves. Standard Specifications for Transportation Materials and Methods of Sampling and Testing. AASHTO LRFD Bridge Design Specifications. This manual is the base bridge design manual that all DOTs ...
Maximum acceptable loss for the base course of the road is 45%; the more demanding surface course must be 35% or less. [1] The test was developed by the city engineers of Los Angeles in the 1920s. [8] The California Highway Commission found the new methodology superior to the established Deval abrasion test, and adopted the LA test in 1927. [8]
FWD data is most often used to calculate stiffness-related parameters of a pavement structure. The process of calculating the elastic moduli of individual layers in a multi-layer system (e.g. asphalt concrete on top of a base course on top of the subgrade) based on surface deflections is known as "backcalculation", as there is no closed-form solution.
Pavement design methods are continuously evolving. Among these are the Shell Pavement design method, and the American Association of State Highway and Transportation Officials (AASHTO) 1993/98 "Guide for Design of Pavement Structures". A mechanistic-empirical design guide was developed through the NCHRP process, resulting in the Mechanistic ...
The base course is 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. [citation needed]