基于流变和微观分析的PR改性沥青老化性能评价

Evaluation of Aging Properties of PR Modified Asphalt Based on Rheological and Microscopic Analysis

针对自主研发的橡胶树脂(PR)改性沥青进行了老化性能研究。采用薄膜老化烘箱和自主设计研发的紫外老化烘箱模拟沥青的热氧老化和光氧老化过程,对老化前后的PR改性沥青进行了常规性能试验、流变试验和凝胶色谱的试验对比。结果表明:PR改性技术能够很好地提高沥青的抗老化性能;PR改性沥青老化后针入度、软化点性能改变不大且RTFOT老化后高温等级较高,另外PR改性沥青的分子量分布曲线变化较小,其耐老化性能得到明显改善;可以采用沥青的重均分子量和分散度进行宏观性能的部分表征,沥青重均分子量和分散度越大,沥青温度敏感性越小,耐老化性能越好。

Rubber resin(PR) modified asphalt was obtained by a kind of specially treated PR and SBR with simple mechanical mixing. An ultraviolet aging oven was designed and developed. First of all, the thermal oxidative and photooxidation aging of the asphalt were simulated by using film aging oven and ultraviolet aging oven. The conventional properties test, rheological test and gel chromatography molecular weight distribution of PR modified asphalt before and after aging were compared. The results show that the modification of PR can improve the aging property of asphalt. Its aging resistance can be improved by even the small performance changes of the penetration. The softening point of the asphalt after aging changes little and its higher temperature levels becomes higher after aging by the test of RTFOT, which is consistent with that the molecular weight distribution curve of PR modified asphalt is smaller. The average molecular weight and dispersity of asphalt can be used to characterize the macroscopic properties of asphalt. The greater the molecular weight, and the greater the dispersion, the smaller the temperature sensitivity, and the better the aging resistance of the asphalt will be.