Rheological Behavior of Polyphosphoric Acid-Vulcanized Liquid Rubber Compound Modified Asphalt Binder

The purpose of the study was to improve the anti-rutting property of liquid rubber (LR) asphalt binder. In this study, polyphosphoric acid-vulcanized liquid rubber (PPA-VLR) compound asphalt binder was prepared, and the effect of PPA concentration on binder’s physical and rheological behavior was investigated. The influence of PPA on anti-cracking performance of VLR asphalt was evaluated from various perspectives. Results proved that, with an increase in PPA content, the resistance to rutting of PPA-VLR compound modified asphalt was dramatically improved. Also, the added 1.6 wt% PPA led to the best anti-rutting enhancement and delayed the short- and long-term aging of the binder. Furthermore, the modification of PPA did not affect the PPA-VLR modified asphalt’s anti-cracking property significantly, which meant that PPA-VLR modified asphalt binder maintained an acceptable performance at low temperatures. The chemical fusion in PPA could increase the proportion of high-average molecular weight components. Overall, the incorporation of PPA would provide a basic reference, to extend the applying range of asphalt LR technology.