多聚磷酸及橡胶粉复合改性沥青性能
Properties of composite？？modified asphalt with polyphosphoric acid and rubber powder

为研究多聚磷酸（PPA）与橡胶粉复合改性沥青的综合性能，以更好地确定其适用条件。分别采用常规试验及动态剪切流变试验，通过针入度、软化点、延度、针入度比、车辙因子、相位角、复数模量指数等指标，对不同橡胶粉含量及不同PPA掺量的改性沥青进行研究，详细评价PPA及橡胶粉复合改性后的高低温性能、感温性能及短期老化性能。结果表明：复合改性沥青高温性能得到很大提升，软化点提高，抗车辙因子较基质沥青提高了5~20倍；动态剪切流变试验中，在高温高频率条件下，复合改性沥青的储存模量随着频率增加而增大，在中国道路行驶的允许车速范围内，随着车速的增加，改性沥青的弹性性能表现更佳，利于沥青路面的抗车辙作用；掺入PPA及橡胶粉改性对沥青的延度并无改善，且掺量越多，对沥青延度降低幅度越大，低温抗裂性能下降；复合改性后，沥青复数模量指数（GTS）斜率变小，说明感温性能得到提升；对于老化性能来说，掺入PPA能提高沥青老化前后的抗车辙因子，相位角增加的范围也较小，PPA复配橡胶粉改性沥青老化前后高温抗变形能力优于橡胶粉单一改性沥青。综合看来，掺入PPA能有效改善橡胶粉改性沥青的高温性能、感温性能及短期老化性能，其中，掺量（质量分数，下同）1.5%PPA+15%橡胶粉复合改性沥青整体性能相对最佳。
In order to study the comprehensive performance of polyphosphoric acid (PPA) and rubber powder composite modified asphalt and its applicable conditions were investigated. Conventional and dynamic shear rheological tests were conducted, using indicators of the degree of targeting, softening point, ductility, penetration ratio, rutting factor，phase angle, and complex modulus index. Composite？？modified asphalts with different contents of rubber powder PPA were studied. The high？？ and low？？temperature performance, as well as the temperature？？sensitive and aging properties, were evaluated in detail. The results show that the high？？temperature performance of composite？？modified asphalt is significantly improved, the softening point is higher, and the anti？？rutting factor is approximately 5 to 20 times higher than that of the matrix asphalt. The deformation of asphalt is smaller under conditions of high temperature and large frequency, which is beneficial to the anti？？rutting effect of asphalt，in a dynamic shear rheological test. The elastic property is better under a permissible speed, which is beneficial to the anti？？rutting of pavements. However, the addition of PPA and rubber powder does not improve the ductility of the asphalt. The higher the amount of asphalt, the greater the decrease in its ductility. Further, the low？？temperature performance of the asphalt decreases. The slope of the complex modulus index (GTS) of the modified asphalt declines, indicating that the temperature sensing performance is improved. The blending of the PPA can upgrade the anti？？rutting factor of asphalt aging, lowering the degree of phase angle increase. The high？？temperature deformation resistance of asphalt modified with PPA and compound rubber powder is better than that using only modified rubber powder. Therefore, the incorporation of PPA can effectively improve the high？？ and low？？temperature performance, as well as the temperature？？sensitive and aging properties. Among the results, 1.5% PPA+15% rubber powder composite modified