A Study of the Basic Strength Components of Asphaltic Concrete

Generally speaking, pavements may be divided into two broad classifications, i.e. rigid and flexible. The term rigid pavement is applied only to wearing surfaces constructed of Portland Cement Concrete. The term flexible is used to denote the tendency of all layers to conform to the same shape under traffic. The basic concept in the design of flexible pavement is that a load applied to the surface is distributed over successively larger areas, as it is transmitted through each lower layer or course, until it has become so diminished in its intensity as to be less than the strength of the natural soil upon which the pavement rests. Therefore, the thickness of the flexible pavement structure is a function of the traffic loads, the load supporting characteristics of the native soil, and the structural properties of the several courses. It is the primary purpose of this study to evaluate with greater accuracy than has been done previously, the basic strength components of the bituminous surface course. The resistance to deformation under sustained or repeated loads. This resistance to deformation generally manifests itself in the form of cohesion, frictional resistance, and interlocking resistance. The process of mixture design must combine these three strength components so as to obtain a maximum resistance to deformation