多聚磷酸改性沥青及其混合料低温性能研究

采用常规低温性能试验和Superpave低温性能试验,研究了不同类型多聚磷酸(PPA)改性沥青胶结料的低温性能,对比分析了沥青胶结料低温性能评价指标之间的相应关系,并采用小梁弯曲试验和冻断试验验证了沥青混合料的低温抗裂性能,研究了沥青胶结料与混合料低温性能之间的相关性.最后对不同低温性能评价指标的合理性和不足之处进行了较为深入的分析.结果表明,PPA掺入减小了沥青的延度和劲度模量,老化对PPA改性沥青低温性能的影响显著;应变能密度指标表明PPA可以改善沥青混合料低温抗裂性;PPA复配SBR的改性沥青低温效果要优于SBR改性沥青;冻断温度与冻断强度能较准确地评价多聚磷酸改性沥青混合料的低温抗裂性能.

Study on Low Temperature Performance of Polyphosphoric Acid Modified Asphalt and Asphalt Mixture

Through the conventional low temperature performance test and Superpave low temperature performance test, the structural performance of different polyphosphoric acid(PPA) modified asphalt binder was investigated at low temperature, and the corresponding relationship of its performance evaluation index was analyzed. Further, the anti-cracking performance of asphalt mixture at low temperature was verified by the improved trabecular bending test and TSRST, and the correlation of low temperature performance between the asphalt binder and the mixture was studied. Finally, the rationality and deficiency of the evaluation index of different low temperature performance were analyzed. The results show that PPA reduced the ductility and stiffness modulus of asphalt, and the aging had great influence on the structural performance of PPA modified asphalt at low temperature. The strain energy density index shows that PPA can improve the cracking resistance of asphalt mixture at low temperature, the anti-cracking performance of PPA compound SBR modified asphalt was better than that of SBR modified asphalt, and the freezing temperature and freeze fracture strength can more accurately evaluate the low temperature performance of PPA modified asphalt.