Gradation Optimization Of Crumb Rubber Modified Asphalt Mixture Based On Bailey Design Method

Nowadays,the production of waste tires is growing in China.How to deal with these "black pollution" has become an urgent problem.It is an effective way to use the rubber in asphalt pavement.There has been a lot of research on the crumb rubber modified asphalt mixture,including Dry Process and Wet Process.Compare with wet process,dry process have many advantages: the production process is simple,consume more rubber,better high temperature stability,do less harm to the environment.At present,the ordinary gradation design method is still used in crumb rubber modified asphalt concrete,it didn’t consider the influence of rubber on the asphalt mixture volume index.So that the performance of crumb rubber modified asphalt concrete(Dry Process)is unstable,it is prone to peeling,loose,cracks and other early diseases.In view of this,it’s of great significance to optimize and design the gradation of crumb rubber modified asphalt mixture.We selected SMA-13 as the research object,and selected the design density of 95%,100%,105% and 110% to design the aggregate gradation and use the rubber to replace the 0.4%,0.8%(accounting for the total mass of mineral aggregate)so that the fine aggregate does not destroy the main skeleton.And the mortar of fine aggregate and asphalt provide adequate cohesion,durability,water stability.Then,to do the experiments on the crumb rubber modified asphalt mixture to test road performance testing.The results showed that:rubber modified asphalt concrete(Dry Process)have shown good high temperature anti-rutting performance,low temperature crack resistance can meet the specifications.Water stability can also meet regulatory requirements.And anti-permanent deformation ability is also good.Through the analysis of test results,design density between 100%-105%,rubber powder replacement of 0.8% when the performance is relatively better.Therefore,to optimize the gradation of SMA crumb rubber modified asphalt mixture can improve its high temperature performance,and low temperature performance and water stability can meet the practical application requirements.