新旧沥青拌和度对掺加RAP的再生沥青混合料水稳定性的影响  

Effect of Blending Degree of Aged and Virgin Binder on Moisture Stability of Asphalt Mixture with RAP

作　　者：管鑫 侯向导 GUAN Xin;HOU Xiangdao

机构地区：[1]同济大学道路与交通工程教育部重点实验室,上海201804

出　　处：《上海公路》2021年第2期107-112,M0006,M0007,共8页Shanghai Highways

摘　　要：回收沥青铺面(RAP)是指将旧沥青路面铣刨、回收、破碎、筛分后得到的固体颗粒物,其表面一般裹覆有旧沥青。RAP与新集料及新沥青的拌和过程中,其表面的旧沥青可部分发挥作用,从而起到节约沥青用量、改善混合料性能的作用。为探究新旧沥青拌和度对掺加RAP的再生沥青混合料水稳定性的影响,首先利用间接拉伸试验研究了拌和条件(拌和温度和拌和时间)对再生沥青混合料水稳定性的影响,引入拌和效率模型,建立了拌和度与劈裂抗拉试验强度比(TSR)之间的关系,并利用图像识别技术,探究了再生沥青混合料劈裂破坏的机理。结果表明,随着拌和温度提高和拌和时间延长,再生沥青混合料的水稳定性先增强后减弱;拌和度与水稳定性之间存在正相关关系,新旧沥青的充分拌和可以改善沥青混合料的性能;随着拌和时间延长,再生沥青混合料内部的黏聚性破坏逐渐增多。Reclaimed asphalt pavement(RAP)refers to the solid particles obtained from waste asphalt pavement,whose surface is generally covered with aged asphalt.During the mixing process of RAP with aggregate and virgin asphalt,the aged asphalt on the surface can only be partly effective,which can save the amount of asphalt and improve the performance of the recycled asphalt mixture.In order to explore the influence of blending degree between virgin and old asphalt on the moisture stability of the recycled asphalt mixture mixed with RAP,the influence of mixing process,i.e.,mixing temperature and mixing time on mixture moisture stability was studied by indirect tensile strength(ITS)test firstly.A blending efficiency model was introduced to establish the relation between blending degree and tensile strength ratio(TSR).Besides,the tensile failure mechanism was explored by image recognition technology.The results indicated that the increase of mixing temperature and mixing time improved the moisture stability first and then tended to weak it.Meanwhile,there was a positive relation between moisture stability and blending degree,which meant a sufficient mixing between aged and virgin binder could help the improvement of asphalt mixture properties.Besides,it could be inferred that cohesive failure inside the recycled asphalt mixture increased with the mixing time.

关 键 词：拌和温度 拌和时间 拌和度 再生沥青铺面(RAP) 水稳定性 劈裂抗拉强度 

分 类 号：U414[交通运输工程—道路与铁道工程]