An optimized fatigue model of asphalt binder combining nonlinear viscoelastic and intrinsic healing characteristics

Abstract

This paper proposed an optimized fatigue life prediction model of graphene oxide (GO) modified asphalt binder considering the coupled effects of nonlinear viscoelasticity (NLVE) and intrinsic healing compensation. The equivalent nonlinear complex modulus (|G*|NLVE) was quantified accordingly and an NLVE-based fatigue model was proposed in this study. The parameters damage healing (ΔS'), local life compensation (ΔN), damage healing index (%HS), and local lifetime compensation index (%ΔN) were employed to characterize the intrinsic healing capability and mechanism of GO-modified binders. There is a strong correlation mechanism between the healing compensation effect and the damage healing of asphalt binders during healing intervals, as evidenced by the linear relationship between ΔS' vs. ΔN and %HS vs. %ΔN. Furthermore, the analysis of the total stored pseudo-strain energy counteracting the damage healing reveals that GO-modified binder has greater stiffness and require more stored pseudo-strain energy to counteract ΔS'. The fatigue life of asphalt binder is further prolonged by the healing compensation effect on the basis of GO modification and NLVE effects.