Estimating Moisture Sensitivity of Warm Mix Asphalt Modified with Zycosoil as an Antistrip Agent Using Surface Free Energy Method

Abstract

With increasing interest in the use of warm mix asphalt (WMA) in the paving industry, more studies in this field for improvement of WMA properties seem to be necessary. In past decade, several studies focusing on use of Sasobit and asphamin as warm additives in asphalt mixtures have been conducted; however, the effects of these additives on moisture susceptibility of asphalt mixture are still not fully understood. In this study, the moisture susceptibility of WMA evaluated with and without a new nanotechnology material as antistrip additive (namely Zycosoil) by determining the micromechanisms that affect the adhesion bond between the aggregate and asphalt binder and the cohesion strength of the asphalt binder using the surface free energy (SFE) concept and laboratory testing analysis. Indeed, the primary goal of this research was to decrease the moisture damage in WMA. Two types of aggregates, limestone and granite, and two types of WMA additives, namely Sasobit and aspha-min, in addition to as Zycosoil as an antistrip additive were evaluated in this study. Moisture sensitivity index, which is the percentage of the aggregate surface exposed to water (