Effects of types and content of warm-mix additives on CRMA

Studies in recent years have demonstrated that warm-mix asphalt (WMA) additives can effectively reduce the production temperature of crumb-rubber-modified asphalt (CRMA) mixtures without significantly affecting the engineering properties. CRMA pavement mixtures with WMA additives have several environmentally friendly features. However, there is limited research into the influences of different types and content of WMA additives on CRMA properties. In this paper, CRMAwas created by mixing an asphalt binder with crumb rubber powder of -40 mesh size and 18% by mass of the asphalt. Various application rates of two different WMA additives, Sasobit and Evotherm, were added into the CRMA. CRMAwith and without WMA additives were tested for high-temperature behavior, low-temperature behavior, temperature sensitivity, and fatigue resistance properties. Test results indicate that the types and content of WMA additives have a significant impact on various properties of CRMA. Based on the test results, the optimal type and content of WMA additives may be chosen for CRMA pavement mixtures in different environmental conditions.