高掺量RAP热再生沥青混合料路用性能研究

Research on Road Performance of High Content RAP Hot-Recycled Asphalt Mixture

在保证RAP再生沥青混合料路用性能的同时,如何合理利用废旧沥青混合料,对推进废物再生利用具有重大的意义。文章通过对石安高速上面层刨铣料进行抽提筛分试验,评价RAP材料的相关性能;确定了RAP掺量为20%、30%、40%时再生混合料最佳沥青用量,然后开展浸水马歇尔试验、车辙试验、小梁低温弯曲试验、冻融劈裂试验及再生沥青混合料疲劳试验;同时系统地分析了不同RAP掺量对热再生沥青混合料的疲劳性能、高温稳定性、水稳定性以及低温抗裂性的影响规律。研究表明:回收旧沥青的黏度值、延度及软化点均呈现下降趋势;不同的掺配满足各体积指标要求4.75mm的通过率和最佳沥青用量。

While ensuring the road performance of RAP recycled bituminous mixture, the rational use of waste asphalt mixture is of great significance for promoting the recycling of waste. This article evaluates the relevant properties of RAP materials by extracting and screening tests on the top layer of the Shi＇ an Expressway. After determining the optimal amount of bitumen used for regenerating the mixture when the RAP content was 20%, 30%, and 40%, the Marshall test, rutting test, trabecular low temperature bending test, freeze-thaw cleavage test and fatigue test of recycled asphalt mixture were carried out. At the same time, the influences of dif- ferent RAP content on the fatigue performance, high temperature stability, water stability and low temperature crack resistance of thermal recycled asphalt mixture were systematically analyzed.The results show that the softening point, viscosity value and ductility of recycled asphalt show the downward trend. Different blendings meet the pass rate requirements of 4.75mm and the optimum as- phalt dosage for each volume index.