基于机械分离法的再生粗集料的路用性能

Pavement performance of recycled coarse aggregate based on mechanical separation method

为研究废旧沥青路面材料(reclaimed asphalt pavement,RAP)的机械法油石分离技术,分析再生粗集料的性能,采用洛杉矶磨耗仪对RAP进行磨耗作为再生粗集料,采用磨耗率和分离率评价分离效果,测定不同旋转次数下RAP的磨耗率和分离率随球料质量比的变化,确定最佳工艺参数,采用荧光显微镜观察再生粗集料的微观空隙状态;将再生粗集料、同源普通石灰岩粗集料、抽提的粗集料分别与细集料拌制稀浆混合料应用于微表处中,研究不同材料对微表处性能的影响。结果表明:油石分离的最佳工艺参数为磨耗仪旋转900次,磨料用小球与RAP的质量比为1.0;再生粗集料表面仍残留沥青,填充于开口空隙中;与其他2种粗集料相比,再生粗集料制备的微表处混合料的可拌和时间延长,配伍性及抗水害性能明显提升,油石比下降,可有效节省乳化沥青。再生粗集料可作为微表处中的新集料使用,性能优越,施工成本降低。

To study the mechanical hot-mix separation technology for reclaimed asphalt pavement(RAP)and the performance of recycled coarse aggregates,the RAP is subjected to abrasion using a Los Angeles abrasion machine to obtain the recycled coarse aggregates.The abrasion rate and separation rate are used to evaluate the separation effectiveness.The abrasion rate and separation rate of RAP at different rotation counts are measured to determine the optimal process parameters.The micro-pore structure of the recycled coarse aggregates is observed using a fluorescence microscope.The recycled coarse aggregates,conventional limestone coarse aggregates from the same source,and extracted coarse aggregates are mixed with fine aggregates to prepare slurry mixtures for application in micro-surfacing.The influence of different materials on the performance of micro-surfacing is studied.The results show that the optimal process parameters for asphalt-aggregate separation are 900 rotations of the abrasion machine with a mass ratio of 1.0 between the abrasive balls and RAP.Residual asphalt still remains on the surface of the recycled coarse aggregates,which fills the open pores.Compared with the other two types of coarse aggregates,the slurry mixture prepared with recycled coarse aggregates exhibits prolonged mixing time,improved compatibility,increased resistance to water damage,lower asphalt-aggregate ratio,and effective reduction in emulsified asphalt consumption.Recycled coarse aggregates can be used as new aggregates in micro-surfacing,with superior performance and reduced construction costs.