The Study on Pavement Performance of the Different Mixing Rate Regeneration Mixture Based on Reference Material Synthesis
|School||Chongqing Jiaotong University|
|Course||Road and Railway Engineering|
|Keywords||RAP plant mix recycling flexible crushing blending rate datummaterial|
Asphalt pavement recycling technologies were first researched in1970s of20thcentury, its widespreading was in1990s of20thcentury. According to constructionmethods, asphalt pavement recycling technology could be sorted into two type: plantmix recycling and in-place recycling. In-place recycling has to heat the existingpavement to200℃, which will lead to second time aging. However there were twoways to recycle existing pavement materials in plant mix recycling technology,milling and flexible crushing. The advantage of recycling asphalt pavement withflexible crushing method is it can retain the aggregate gradation of existing pavementin as to a largest degree.Gray correlattion method was included in this paper to analyze the variability ofRAP detaileding, accoding to which the variability of RAP and raw materials werecontroled. Based on the controling of variability, the concept of datum material wasadvanced, and datum material sythesizing and standard mix proportioon weresimulated, then a synthesized mix proportion was obtained.In a detailed way, the blending rate of RAP was investigated in this paper. Toincrease the blending rate of RAP, the datum material sythesizing method was used. Itcan be observed by aggregate gradation analysis and performance verification,recycled asphalt pavement obtained by datum material sythesizing method couldreduce the variability of RAP particles and increase the blending rate of RAP. TheMarshall testing protocal was used to deterimine optimune asphalt ratio, it wasconclued that the optimune asphalt ratio of blending rate of50%,60%,70%were4.8%,4.95%,5.1%respectively. The perfprmance of mix with blending rate of50%,60%,70%recycled asphalt pavement could meet the requirement of asphalt mixstandard.Factors that influence the performance of RAP were analyzed in this paper, itwas observed: whether or not datum material was used, blending rate of RAP, dosageof recycling additive, reaction time of mixture and temperature could influence theperformance of recycled asphalt mixture in different degree. Recycled asphalt mixtureobtained by datum material method was better than the one obtained from regularrecycled asphalt pavement. As the blending rate of RAP increased, the performance ofrecycled asphalt mixture reduced, when the blending rate of RAP increased to70%, the performance of recycled aspahlt mixture decreased significantly, thus could notmeet the requirement of mix design standard. Its performance improved as the dosageof recycling additive increased. The longer the reaction time, the better of the effect ofrecycling. As the reaction temperature increased from5℃to60℃, the effect ofrecycling was first increase then decreas, the optimune temperature was about30-35℃.