Thermal analysis on the component interaction of asphalt binders modified with crumb rubber and warm mix additives

Abstract

This study investigated the interaction among different components of asphalt binders collectively modified with crumb rubber and warm mix additives through thermal gravimetric analysis (TGA) and differential scanning calorimeter (DSC) testing. The modified binders were divided into two parts for analysis purpose, namely the extracted crumb rubber modifier (CRM) by removing all asphalt components and the separated binder system by removing insoluble CRM particles. The main findings of this study include that: (1) the interaction between CRM and base asphalt was a component exchange process, i.e., natural rubber and styrene-butadiene rubber were released from CRM and blended with asphalt molecules; (2) wax-based warm mix additives penetrated into CRM during the mixing process; (3) the incorporation of warm mix additives especially the wax-based additives, promoted the component exchange between rubber and asphalt.