Performance Evaluation of Asphalt-Rubber Stone Matrix Asphalt Mixtures with Warm Mix Asphalt Additives

Three kinds of warm mix asphalt (WMA) additives (Sasobit, Evotherm, and CWA) were used in asphalt-rubber stone matrix asphalt (AR-SMA) to reduce the mixing and compaction temperatures of AR-SMA mixtures. In hot mix asphalt (HMA) mixture designs with the same air voids, the compaction temperatures of AR-SMA mixtures with different WMA additives were determined. The wheel tracking test, low temperature beam bending test, and indirect tensile test were conducted in order to evaluate the high temperature performance in terms of the resistance to rutting, the low temperature performance in terms of the resistance to cracking, and the moisture susceptibility of AR-SMA mixtures with WMA additives. The results indicate that the addition of Sasobit can improve high temperature performance significantly relative to the control mixture (AR-SMA without WMA additive), whereas the other additives yield no significant differences. Three WMA additives have significant effects on low-temperature performance, but they do not significantly increase moisture susceptibility relative to the control mixture.