Effects of polyphosphoric acid (<scp>PPA</scp>), <scp>styrene‐butadiene‐styrene</scp> (<scp>SBS</scp>), or rock asphalt on the performance of desulfurized rubber modified asphalt
Hengbin Liu, Zhengqi Zhang, Zhuolin Li, Naiqiang Li
Abstract
Abstract To improve the performance of desulfurized rubber modified asphalt (DRMA), especially its high‐temperature performance, three modifiers (including polyphosphoric acid [PPA], styrene‐butadiene‐styrene [SBS], and rock asphalt) were selected to modify DRMA respectively. The conventional performance, rheological properties, chemical composition, and thermal decomposition were characterized to analyze the performance and modification mechanism of DRMA and its composites. Test results show that, the addition of PPA, SBS, and rock asphalt can all improve the high temperature of DRMA, among which the desulfurized rubber/rock asphalt compound modified asphalt (DRMA‐ROCK) has the best high‐temperature performance; however, its construction workability, storage stability, and low‐temperature performance are poor. In contrast, desulfurized rubber/PPA compound modified asphalt (DRMA‐PPA) not only has better high‐temperature performance, but also has excellent low‐temperature performance, storage stability, and fatigue performance. Fourier infrared spectroscopy (FTIR) test confirms that the modification process of DRMA by these modifiers is chemical modification, and the characteristic peak indexes obtained from FTIR also prove that DRMA‐ROCK has better high‐temperature performance but poor construction workability from the microscopic point of view. Furthermore, thermogravimetric analysis‐differential scanning calorimetry test shows that the addition of rock asphalt improves the thermal stability of DRMA, while PPA and SBS decrease its thermal stability. From the above results, it can be concluded that DRMA‐PPA has excellent comprehensive properties.