A framework to characterize the healing potential of asphalt binder using the linear amplitude sweep test

Abstract

The healing characteristics of asphalt binders affect the fatigue performance of asphalt mixtures and field pavements. The objective of this paper is to quantify the healing potential of asphalt binders using the linear amplitude sweep (LAS) test under various damage level and rest period durations. A healing protocol based on the LAS test is successfully established to measure the healing behaviour of asphalt binder by applying the rest periods before and after cohesive failure. Based on the simplified-viscoelastic continuum damage (S-VECD) model, the percent healing (%HS) is quantified from the healing recovery of the accumulated damage growths. The neat asphalt binder exhibits better %HS results than the SBS modified binder in the pre-failure conditions. However, the SBS modified binder exhibits a higher healing potential in the post-failure case. The rest-damage superposition principle (RDSP) is further investigated in the pre-failure cases to remove and unify the effects of damage level and rest period by constructing a %HS mastercurve at a given reference damage level. The developed healing mastercurve and related damage shift factor can be used to represent the intrinsic healing potential of a given asphalt binder. A series of healing indices are proposed and discussed based on the healing mastercurve to numerically compare the healing performance of asphalt binders.