就地热再生沥青混合料配合比优化设计

Optimization Mix Design of Hot-in-place Recycling of Asphalt Mixture

为提高沥青路面就地热再生沥青混合料的质量,进行混合料配合比优化设计,以甘肃河西地区某高速公路为实际工程案例,对旧沥青路面回收料(RAP)和路面状况进行调查,掌握RAP的级配组成及沥青老化程度,根据调查结果进行沥青路面就地热再生混合料级配优化设计,并通过浸水马歇尔试验、冻融劈裂试验、车辙试验和渗水试验对再生沥青混合料的各项性能进行验证.结果表明:RAP料的级配偏细,回收沥青的老化程度偏高,但仍满足再生要求;外掺沥青混合料与RAP料掺加比例分别为15%和85%,再生剂的掺量为RAP沥青的4%,外掺新沥青为RAP沥青的4.8%;经配合比优化设计的再生沥青混合料的水稳定性、高温稳定性和渗水都能满足规范要求且性能良好.

In order to improve the quality of asphalt pavement in hot-in-place recycling asphalt mixture,and to optimize the mix design of the mixture,based on the practical project of a highway in Hexi Region of Gansu Province,the reclaimed asphalt pavement(RAP)and pavement conditions are investigated to make a good knowledge of the gradation composition of RAP and the aging degree of asphalt.According to the survey,the optimization mix design of hot-in-place Recycling asphalt mixture is carried out.And the performance of the recycled asphalt mixture was verified by Marshall Immersion test,freeze-thaw splitting test,rutting test and seepage test.The results show that the gradation of the RAP is fine,aging degree of recycled asphalt is high,but still meet the regeneration requirements.The ratio of asphalt mixture and RAP was 15%and 85%;the amount of recycling agent was 4%of RAP asphalt;the addition of fresh asphalt was 4.8%of RAP asphalt,The water stability,high temperature stability and water seepage of the recycled asphalt mixture with optimized mix can meet the requirements of the specification and the performance is good.