RAP精分料超薄磨耗层复合改性沥青混合料配合比设计及验证

Mix Design and Verification of RAP Fine Aggregate Ultra-thin Wearing Course Composite Modified Asphalt Mixture

为拓展因路面养护铣刨而产生的大量沥青混合料回收料(RAP)的应用范围,依托油石分离技术,利用物理碰撞方式将玄武岩RAP精分为10~15 mm,5~10 mm,3~5 mm,0~3 mm共4档料,采用复合改性沥青为高黏沥青改善RAP相关性能,进行100%RAP掺量超薄磨耗层的配合比设计,并从高温稳定性、低温抗裂性、水稳定性和构造深度等方面验证其路用性能。研究结果表明:超薄磨耗层最佳新掺油石比为3.0%,最佳综合油石比为6.3%;精分RAP超薄磨耗层的渗水系数极大,将标准马歇尔试件切开,其内部存在较多连通的空隙;精分RAP超薄磨耗层动稳定次数为13404次/mm,远超规范所要求的3000次/mm,表明其高温稳定性优越;而最大弯拉应变仅为2438.694με,表明低温抗裂性较差。

In order to expand the application scope of a large amount of Reclaimed Asphalt Pavement(RAP)produced by pavement maintenance milling,based on the asphalt stone separation technology,this paper uses the physical collision method to finely divide the basalt RAP into four grades of 10-15 mm,5-10 mm,3-5 mm,0-3 mm,uses the composite modified asphalt to improve the relevant properties of RAP for the high viscosity asphalt,carries out the mix design of 100%RAP content ultra-thin wearing course.Its road performance is verified from aspects such as high temperature stability,low temperature crack resistance,water stability,and structural depth.The research shows that the best new asphalt ratio of ultra-thin wearing course is 3.0%,and the best comprehensive asphalt ratio is 6.3%.The water permeability coefficient of the fine RAP ultra-thin wearing layer is very large.When the standard Marshall test piece is cut,there are many connected voids.The dynamic stability times of fine RAP ultra-thin wearing layer is 13404 times/mm,which is far more than 3000 times/mm required by the specification,indicating that its high temperature stability is superior.The maximum bending and tensile strain is only 2438.694με,which shows low temperature crack resistance is poor.