水-热作用下胶粉改性沥青汉堡车辙高温性能

橡胶类改性沥青混合料的高温性能一直是国内外研究的热点问题。本文采用浸水汉堡车辙试验,针对普通橡胶沥青、terminal blend(TB)胶粉改性沥青及TB复合改性沥青混合料在水-热综合作用下的抗车辙性能进行评价与对比。实验结果表明,对于传统橡胶沥青来说,其在浸水条件下的高温抗车辙性能随着掺量的增大而先下降后上升,掺量从5%变化至20%的过程中,橡胶沥青中的橡胶颗粒对沥青分散体系的性能贡献逐渐增大,橡胶粉掺量推荐采用内掺20%。对于TB胶粉改性沥青混合料,其在水-热综合作用下的抗车辙性能劣于基质沥青混合料,且随掺量的增加而逐步下降。对于TB+SBS复合改性沥青混合料,SBS的掺入能够显著提高TB胶粉沥青混合料在水-热综合作用下的抗车辙性能,且性能随SBS掺量的增加而提升。根据实验结果,在TB+SBS复合改性沥青混合料中推荐使用20%橡胶沥青,SBS的掺量可根据性能与成本进行综合考虑。

Rutting Performance of Rubber-Modified Asphalt Mixture under the Combined Effects of Moisture and High Temperature

The high temperature performance of rubber-modified asphalt mixture has always been a concerned issue in domestic and foreign research. In this study, the Hamburg wheel-tracking test in immersion conditions was performed to compare and evaluate the rutting resistance of the traditional crumb rubber (CR)-modified asphalt, terminal blend (TB) rubberized asphalt and TB composite modified asphalt mixtures under the combined effects of moisture and high temperature. The results indicate that the high-temperature rutting resistance of CR-modified asphalt mixture in water conditions can be declined and then promoted with the rubber dosages. The contribution of rubber particles in CR-modified asphalt to the performance of asphalt dispersion system increases gradually when the CR dosage changes from 5% to 20%. The high-temperature rutting resistance of TB rubberized asphalt mixture in water conditions is inferior to that of the base asphalt mixture. And it decreases with the increase of the TB rubber dosage. For TB composite modified asphalt mixture, the addition of SBS (Styrene butadiene styrene triblock copolymer) modifier can significantly improve the rutting resistance of mixtures under the combined effects of moisture and high temperature. And the performance increases with the SBS contents. According to the experimental results, 20% for crumb rubber is recommended in TB+SBS composite modified asphalt mixture, and the dosage of SBS can be comprehensively considered according to the performance and cost.