RAP料级配变异性对厂拌热再生混合料级配离析的影响研究

Research on the Influence of RAP Material Gradation Variability on the Gradation Segregation of Plant-mixed Hot Recycled Mixture

在选定的RAP料级配范围内选取3种不同级配的RAP料作为基准料来模拟旧料级配的变异性,并且采用分形理论以及变异累积系数来评价采用不同类型的基准料合成的再生沥青混合料的级配变化程度。研究结果表明:RAP料级配的变异性对再生沥青混合料的级配均匀性具有不利影响,并且随着RAP掺量的增加,这种不均匀离析现象更加明显;工程上应尽量减小RAP料级配的变异性,同时采用RAP料级配范围中值后能够降低再生沥青混合料级配的变异性;分形维数D是评价离析类型的相对指标,能够有效表征再生混合料的级配变异特征;变异累积系数S是评价级配离析程度的绝对指标,能够有效表征再生混合料级配的变异程度。

Three RAP materials with different gradations are selected as reference materials in the selected RAP grading range to simulate the gradation variability of reclaimed asphalt pavement materials,and fractal theory and variation accumulation coefficient are used to evaluate the gradation variation degree of recycled asphalt mixture synthesized with different types of reference materials.The results show that the gradation variability of RAP has a negative impact on the gradation uniformity of recycled asphalt mixture,and the segregation becomes more obvious with the increase of RAP content.The variability of RAP grading should be minimized in project practice,and the median value of RAP grading range can reduce the variability of recycled asphalt mixture.In addition,the fractal dimension D is a relative index to evaluate the segregation types,which can effectively represent the gradation variation characteristics of the recycled mixture.The variation accumulation coefficient S is an absolute index to evaluate the degree of gradation segregation,which can effectively characterize the degree of variation.