Research On The Performance Of Emulsified Asphalt Plant Mixed Cold Recycled Mixture In Cold Area

In recent years,many expressways have achieved a surge in traffic volume and increasing vehicle load.With the improvement of the highway network,many highgrade highways which have been in service for many years have entered the stage of renovation or maintenance,resulting in a considerable amount of recycled asphalt mixture(RAP).In this paper,it is demonstrated that rap can be recycled in cold climate by using emulsified asphalt plant mixing cold recycling technology.Firstly,the basic data of chanliu Expressway(Lanzhou Section)located in cold area is investigated,and the old pavement condition is evaluated from two aspects of pavement damage condition and rutting depth,and the composition and causes of pavement diseases are analyzed.Taking three kinds of recycled materials milled from different positions of the road section as the test objects,the dispersion of rap was analyzed from three aspects of aging asphalt properties,aging asphalt content and old aggregate gradation.The properties of aged asphalt were determined as the main index of rap quality classification in cold climate by orthogonal test.In order to improve the road performance of emulsified asphalt cold recycling mixture in cold area,the mix proportion of emulsified asphalt cold recycling mixture was optimized from two aspects of synthetic aggregate gradation optimization and emulsified asphalt selection.The results show that the suitable raw materials for cold climate environment are rap(0 ～ 4.75mm): rap(4.75 ～ 9.5mm): rap(9.5 ～ 26.5mm):new aggregate: Cement = 30:15:35:18:2.The influence of different curing time and temperature on the performance of emulsified asphalt recycled mixture was analyzed by simulating the climate environment in cold area.The test results show that the curing time of emulsified asphalt cold recycling mixture should be more than 7 days,and the curing temperature must be more than 15℃.