多聚磷酸改性沥青流变特性及改性机理

Study on the Rheological Properties and Mechanism of Polyphosphoric Acid Modified Asphalt LIU Hongying, ZHANG Zhenxing, CHANG Rui, HAO Peiwen

摘要:

采用动态剪切流变、重复蠕变和弯曲梁流变等试验分别对多聚磷酸改性沥青、聚合物改性沥青以及聚合物复配多聚磷酸改性沥青在高、低温状态下的流变特性进行了系统研究.结果表明，多聚磷酸能够改善基质沥青和聚合物改性沥青的高低温性能；多聚磷酸与苯乙烯丁二烯苯乙烯嵌段共聚物（SBS）改性剂在改善沥青高温性能机制上存在明显不同，多聚磷酸的掺入显著增加了沥青的黏度，而对沥青的弹性变形恢复能力贡献较小，而SBS改性剂可大幅度提高沥青的弹性变形恢复能力.采用核磁共振（NMR）试验对多聚磷酸改性沥青的改性机理进行了初步分析，发现多聚磷酸与沥青发生了接枝、磷酸酯化和环化反应，从而改变了沥青的碳链结构和化学结构，宏观上使沥青变得更加黏稠.

关键词:道路工程; 多聚磷酸; 改性沥青; 流变特性; 改性机理

Abstract:

Through dynamic shear rheological (DSR), repeated creep and recovery teat(RCRT) and bending beam rheological(BBR) test, the rheological behavior of polyphosphoric acid (PPA)modified asphalt, polymer modified asphalt and polymer mixed PPA modified asphalt at different temperature were comprehensively studied. The results show that the PPA additive can improve performances of matrix asphalt and polymer modified asphalt at the high and low temperature. The modification mechanism had more different performance between PPA and SBS modified asphalt at high temperature, and PPA using can significantly increase the viscosity of asphalt, and PPA has less influence on the elastic deformation recovery ability of asphalt, but SBS can greatly improve the elastic recovery of asphalt. The modification mechanism of PPA modified asphalt was analyzed by nuclear magnetic resonance (NMR) test, and the results show grafting, phosphating and cyclization reactions are happened between asphalt and PPA, which changes the carbon chain structure and chemical structure of asphalt, and asphalt become more viscosity.

Key words:road engineering; poly phosphoric acid; modified asphalt; rheological properties; modified mechanism