Stress-strain behaviour of asphalt concrete in compression

Abstract

This paper presents an evaluation of the failure mode of asphalt concrete and describes the stress-strain curve that governs asphalt concrete beyond the limit of elasticity in the ascending branch. The relationship of stress-strain is identical to that of cement concrete in compression. A general form of the behavioural curve is proposed to represent the elastic and plastic - damage of asphalt concrete. The nonlinear behaviour of asphalt concrete beyond the linear elastic limit swelling is visible to the naked eye. These parameters that define this form are physically significant and are determined experimentally. The parameters of the stress-strain curve are fundamental characteristics of a solid subjected to short term loading. The experiments used short term static compression loading on cylindrical asphalt concrete specimens, differing in mix types (Dense graded, Stone Matrix), air voids content, density, specimen size and temperature. There were significant changes in the peak stress and strains between the asphalt concrete mix types. Different strengths are attainable between asphalt concrete types as well as the properties of the mix constituents. The proposed equations fit a wide range of testing conditions and asphalt concrete type for both the ascending and descending branches of the stress-strain diagram in compression. The investigation derives parameters (yield stress and elastic modulus) for different asphalt concrete mix types which can be used in FE programs such as Abaqus that uses the elastic as well as plastic data to model the behaviour of different mix types of asphalt concrete material used in a pavement structure.