LAUSR

ABSTRACT Moisture-induced damage in asphalt concrete is a major concern to the transportation agencies. Existing moisture sensitivity tests are mostly conducted at the macro- or micro-level and focused on the qualitative measurements only. In this study, the atomic force microscopy (AFM) technology is utilized to investigate moisture susceptibility of asphalt binders through the estimation of nano-level dissipated energy (DE). For the comparison of the AFM test results, two macro-level tests data are also used. Asphalt binders used in this study include a Performance Grade (PG) base binder (PG 64-22) along with its modified counterparts, which are blended with polyphosphoric acid (PPA), styrene–butadiene-styrene (SBS), and SBS plus PPA. Additionally, the effects of three different types of liquid anti-stripping agents (LAA) were investigated. The test specimens of these binder samples were prepared under dry and wet conditions, and their DE values were estimated from AFM tests. Results showed that the base binder and the PPA-modified binder had higher DE values than the SBS- or the SBS + PPA-modified binders. Among all the LAAs, Evotherm showed better resistance to moisture damage than the other ones. Findings of this study are expected to help highway agencies to quantify the moisture resistance of asphalt materials precisely.