Abstract: To study the influence of RAP (Recycled Asphalt Pavement) particle size on the properties of hot recycled asphalt mixture, the gross bulk density and Marshall stability index were selected to evaluate the fusion of new and old asphalt, and a better mixing process was obtained. The ratio of fine RAP in the reference material was changed. Marshall test, rutting test, low temperature trabecular bending test and freeze-thaw split test were used to study the influence of different fine RAP ratios on volume index, mechanical index and road performance of recycled asphalt mixture. The research results show that the “recycled dry mixing method” can improve the fusion of new and old asphalt and the uniformity of mixture mixing in recycled asphalt mixture, and improve the performance of recycled asphalt mixture. The gross bulk density and Marshall stability index of recycled asphalt mixture have the peak value with the increase of the fine RAP ratio. When the proportion of fine RAP in the reference material reaches 13%, the gross bulk density of recycled asphalt mixture is the largest, and when the ratio of fine RAP reaches 17.5%, the Marshall stability of recycled asphalt mixture is the largest. As the proportion of fine RAP increases, the road performance of recycled asphalt mixture has a peak value. When the fine RAP content exceeds 13%, the road performance of recycled asphalt mixture begins to decline. The high proportion of fine RAP will cause the lack of free fine aggregate to fill the gap, and the performance of recycled asphalt mixture will decline. The reference material combination designed by the grey correlation analysis method can effectively compensate the adverse effects of high RAP content on the recycled asphalt pavement.

Key words: highway engineering, hot recycled, reference materials, fusion, road performance

摘要： 为研究RAP粒径对热再生沥青混合料性能的影响，采用毛体积密度和马歇尔稳定度指标，对新旧沥青融合性进行评价，得到新旧沥青融合性较好的拌合工艺。改变基准料中细RAP比例，采用马歇尔试验、车辙试验、低温小梁弯曲试验和冻融劈裂试验，研究不同细RAP比例对再生沥青混合料体积指标、力学指标和路用性能的影响。研究结果表明：“再生干拌法”能提高再生沥青混合料中新旧沥青的融合性和混合料拌合的均匀性，提高再生沥青混合料性能；再生沥青混合料毛体积密度和马歇尔稳定度随细RAP比例升高出现峰值，基准料中细RAP比例达到13%时，再生沥青混合料毛体积密度最大，细RAP比例达到17.5%时，再生沥青混合料马歇尔稳定度最大；随着细RAP比例增加，再生沥青混合料路用性能出现峰值，细RAP掺量超过13%时，再生沥青混合料路用性能开始下降，高比例细RAP会导致再生沥青混合料缺少自由细矿料填充空隙，再生沥青混合料性能下降；用灰色关联度分析法设计的基准料组合能有效弥补高RAP掺量对再生沥青路面带来的不利影响。

关键词: 道路工程, 热再生, 基准料, 融合性, 路用性能