Study On Road Performance Of Warm Mix Recycled Asphalt In South China

Many roads in southern China which have been in service since 2000 have reached the end of their life.Such lot of road renovations and reconstructions have put tremendous pressure on road's maintenance.Recycled asphalt is a new technology for road construction,which has solved the current environmental issue.Warm mixed recycled asphalt is a new road technology which combining asphalt warm mix technology and asphalt regeneration technology.On the one hand,the low construction temperature of asphalt can greatly alleviate the waste of energy in the asphalt construction process,on the other hand,the use of warm mixed recycled asphalt can enhance the compaction characteristics in asphalt construction,making the asphalt pavement easy to be compacted and increasing the amount of old materials.There are few practical applications of warm mixed recycled asphalt mixture in south China,so this field is still in the stage of exploration and research.Therefore,this paper uses the grading of south China to start a research on warm mixed recycled asphalt,which will give some guidance in south China's asphalt mixture regeneration construction.This paper rely on an application fund(Guangdong Research Institute 2017-14)to carry out the research.The main tests are divided into:(1)The asphalt extracted from the old material is used as a raw material to be blended with the new asphalt,and then the three major indexes and the 135°C kinematic viscosity test are carried out on it.Firstly,the trend of the mixed asphalt under the action of regenerant and warming agent is studied.Then the trend of the mixed asphalt under the synergistic effect of warming agent and regenerant is studied.(2)GAC-16,a common grader in South China,is used as the design grading to design the mix ratio of hot-recycled materials.And the best oil-stone ratio of hot-recycled materials can be use as the best oil-stone ratio of WRMA,the compaction temperature of WRMA can be determined by equal volume principle.(3)This paper selects high temperature performance,water stability performance and compaction characteristics as the road performance index of warm mixed recycled asphalt mixture in South China.The high temperature rutting and water stability of the warm recycled asphalt mixture and the hot recycled asphalt mixture(use GAC-16 design)are compared.The water stability test included residual stability test and freeze-thaw splitting test.At the same time,the compaction characteristics of the warm recycled asphalt mixture and the hot recycled material were compared,which by Marshall deformation test and rotary compaction shear test.(4)Using the admixtures of this paper,the surface layer construction of the field experimental is laid,the gas and dust emission data of the construction process is tracked.It is found that the gas and dust emission of the warm recycled asphalt mixture is 50% less than the hot one,which means the warm recycled asphalt mixture is the better material.It contains the better environmental benefits.At the same time,the post-construction road are tested for compaction,water seepage and structural depth.The test data are basically consistent to laboratory results,which proves the feasibility of warm mix technology in practical engineering applications.