Research On The Performance Of Asphalt Cold Recycled Mixture And Pavement Structure

China's highway has developed rapidly,and the number of newly built and opened highway mileage has greatly increased due to the continuous advancement of economic construction,But at the same time,a large number of long-built and long-used highways have reached the design and service life,driving comfort and safety are reduced,so the development stage of highway in China has changed from construction to both construction and maintenance after the "Twelfth Five-Year Plan".The advent of highway maintenance era indicates that a large number of asphalt wastes will be produced during pavement renovation and maintenance.If asphalt wastes are recycled and reused for pavement construction,it will bring significant economic,social and environmental benefits.Therefore,it is necessary to research the recycling of asphalt pavement waste and recycled pavement structure.Based on Pingshuoxian Pavement Reconstruction Project,cold recycled asphalt mixture and pavement structure with recycled layer are studied in this paper.The main research contents are as follows:(1)The original pavement structure,traffic volume and main pavement diseases of Pingshuoxian experimental section were investigated and analyzed,and the causes of main pavement diseases were summarized.The raw materials needed for old asphalt pavement recycling were tested and analyzed,the strength formation mechanism of emulsified asphalt recycled mixture was analyzed,and the maintenance scheme of pavement structure was put forward.(2)In this paper,the design method and steps of cold recycled asphalt mixture were systematically studied,the aggregate gradation was redesigned,and relevant experiments were carried out to determine the best liquid content,the best emulsified asphalt content of recycled mixtures;Based on mix design,the strength characteristics,high temperature stability,water stability and low temperature crack resistance of recycled mixtures were studied.(3)Using ABAQUS finite element software to establish three-dimensional calculation model,combined with design index of pavement structure with recycled layer,the static response of the pavement structure with recycled lower-layer under different axle loads,horizontal forces and thicknesses of recycled layer is analyzed,the regression formula of maximum shear stress of recycled layer is fitted,and the dynamic response of pavement structure under non-uniform moving load is analyzed and studied.(4)Using the established three-dimensional model of pavement structure with recycled lower-layer to study pavement rutting,the effects of temperature,axle load,number of axle load actions,speed and thickness of recyled layer on pavement rutting are analyzed,and the correlation degree of influencing factors of rutting depth is analyzed.Combined with temperature field and traffic distribution in a day,the rutting depth of pavement structure with recycled lower-layer in design life is calculated,and analyze the law of pavement rutting development.