Influence of Compound Action of Rubber Powder and SBS on High-Temperature Performance of Asphalt Pavement Surface

Due to the increase in the number of vehicles on the road, the amount of used vehicle tires has also increased exponentially. Making tires into rubber powder and adding them into asphalt, which forms asphalt rubber as a kind of asphalt binder of asphalt pavement surface, is an effective way of using waste tires. Styrenic block copolymers (SBS) can improve high-temperature performance of asphalt as a kind of polymer additive. Comprehensive recycling rubber powder and SBS in asphalt mixture can not only make use of waste tires, but also expand the application of waste materials and compose environmentally friendly mixture for the asphalt pavement surface, which improves service life and service function of asphalt pavements. In order to evaluate the high-temperature performance improvement of composite-modified asphalt material, three different asphalt binders and two different asphalt mixture types were selected and the related tests were conducted. The results show that for the mixture of SMA-13 and SMA-16, composite-modified asphalt mixture had better high-temperature performance than asphalt rubber mixture, but worse than SBS asphalt. In addition, the crumb rubber (CR)/SBS composite-modified asphalt had a large internal friction angle, which could give better cohesive force for aggregate gradation. Finally, CR/SBS composite-modified asphalt had the smallest reduction rate from 50°C to 70°C. This study identifies that compound action of rubber powder and SBS is an optimal choice for asphalt pavement surface in high-temperature season. It provides a wider range of applications for asphalt rubber in the road construction field, which also realizes waste cyclic utilization and environmental protection.