Effects of Aging on Micromechanical Properties of Asphalt Binder Using AFM

Abstract

The performance of an asphalt binder is closely related to its microstructure. Understanding the properties of asphalt binders at the nano/microscale may help to improve knowledge of their macroperformance. The emergence of atomic force microscopy (AFM) technology makes it possible to distinguish the microstructural and micromechanical properties of asphalt binder. In this paper, the effects of aging and modifiers on the micromechanical properties of asphalt binder were investigated by using AFM peak force quantitative nanomechanical mapping (PFQNM) mode. Four different virgin asphalt binders and one styrene-butadiene-styrene (SBS)-modified asphalt binder subjected to different aging conditions were considered. It is found that the variation of morphology of bee structures relates to the penetration grade. The Derjaguin-Muller-Toporov (DMT) modulus fluctuates violently inside the bee structure. With the increasing aging degree of asphalt binders, the DMT modulus for three phases (catana, peri, and para phases) all increase correspondingly. Moreover, the addition of modifier improves the microscopic properties of asphalt binder.