Thermal behaviour of extracted rubber from hot and warm rubberized asphalt binders

Abstract

This study investigated the thermal behaviour of Crumb Rubber Modifier (CRM) extracted from hot Asphalt Rubber (AR) and warm AR binders through Differential Scanning Calorimeter (DSC) testing and Thermal Gravimetric Analysis (TGA). Three methods were implemented to extract CRM from the modified binders, which resulted in the following findings: 1) the interaction between CRM and base binder is a component exchange process: i.e., natural rubber and styrene-butadiene rubber are released from CRM and blended with asphalt molecules; 2) different Warm Mix Asphalt (WMA) additives have different effects on the interaction between asphalt and rubber: wax based additives penetrate into CRM while the liquid chemical additive rarely interacts with the rubber modifier; and 3) the incorporation of WMA additives, especially the wax based additives, promotes the component exchange process between rubber and asphalt.