One‐Dimensional Constitutive Modeling of Asphalt Concrete

TLDR

Literature identifies vis‑elastic relaxation and fatigue damage as key mechanisms governing asphalt concrete’s inelastic stress‑strain behavior. The study develops a mechanistic constitutive model for asphalt concrete under repetitive loading with rest periods. The model uses Schapery’s nonlinear viscoelastic correspondence principle to separate vis‑elastic relaxation from fatigue damage, represents damage growth via a microcrack‑based parameter, and is validated against random multilevel loading with variable rest periods. The constitutive equation accurately predicts load‑sequence effects and demonstrates the beneficial influence of rest periods.

Abstract

This paper presents a mechanistic approach to constitutive modeling of asphalt concrete under complicated repetitive loading conditions with rest periods. From an extensive literature review, two mechanisms are identified as important to understanding of inelastic stress‐strain behavior of asphalt concrete: vis‐coelastic relaxation and fatigue as a damage accumulation process. The nonlinear viscoelastic correspondence principle developed by Schapery is applied to separate the influences of these two mechanisms to the stress‐strain hysteresis behavior of asphalt concrete. The damage growth in asphalt concrete beam samples is modeled by a damage parameter that is based on a generalization of microcrack growth law. In the verification stage, a random sequence of multilevel loading with random durations of rest periods was applied. The resulting constitutive equation satisfactorily predicts the effect of the sequence of the load applications of varying magnitudes, as well as the beneficial effect of rest periods.