Application of the Viscoelastic Continuum Damage Theory to Study the Fatigue Performance of Asphalt Mixtures—A Literature Review

Abstract

A viscoelastic continuum damage (VECD) model, which accounts for the effects of rate-dependent damage growth, has been successfully applied to quantify the reduction in the material integrity as a function of damage accumulation (characteristic curve) of asphalt mixtures. This paper presents an overview of the fundamentals of the VECD model and its simplifications (S-VECD) applied to the damage characterization of asphalt mixtures. It also presents a laboratory study carried out to evaluate the effects of the addition of reclaimed asphalt pavements (RAP) and a new binder (PG 64-22 or PG 58-16) on the fatigue performance of fine aggregate matrices (FAMs), in which the S-VECD theory was applied to analyze the results. The addition of RAP increased the stiffness and reduced the relaxation rate, resulting in FAMs that were stiffer and more susceptible to damage at high strain levels. The FAMs’ fatigue factors (FFFAM) indicated that the increase in RAP from 20% to 40% decreased the fatigue life of the mixtures. A strict control of the mixture variables is required, since the intrinsic heterogeneity of asphalt mixtures can lead to different characteristic curves for the same material.