Study On Mechanical Properties Of Asphalt Pavement Structure Of Combined Base Course Based On Creep Characteristics Of Surface Laye

Semi-rigid asphalt pavement is the main structural form of urban high-grade pavement in China,which has been widely used at home and abroad for a long time,but it is easy to appear rutting,subsidence,fatigue cracking and other damage soon after the completion of the project.The life cycle of safe operation is generally less than that of design life,so it is urgent to develop a new type of long life composite pavement.In view of this,some scholars in our country have put forward the structural form of composite base asphalt pavement,that is,the base is a semi-rigid base made up of inorganic binder stabilized aggregate and other materials,and the upper base is a flexible base of asphalt stabilized crushed stone or graded crushed stone.The structure form of asphalt concrete as surface layer.In order to prevent reflection cracks,the effect of graded crushed stone composite base pavement is not as good as that of asphalt stabilized macadam.At the same time,the thickness of pavement structure layer and the modulus of asphalt mixture directly affect the stress of pavement.Therefore,through the introduction of domestic and foreign combined base asphalt pavement design concept,taking asphalt stabilized macadam composite base asphalt pavement as the research object,with the help of Abaqus finite element software,The concrete influence of the thickness and modulus of the pavement structure layer on the road mechanical properties is analyzed.(1)By comparing the differences and characteristics between the semi-rigid base asphalt pavement in China and the foreign long-life asphalt pavement,this paper puts forward the superiority of the combined asphalt pavement,and explains the present research situation and prospect of the long-life asphalt pavement at home and abroad.(2)The theory of elastic layered system and finite element numerical value analysis method of existing asphalt pavement structure analysis method are compared and summarized in this paper.The results show that 3D finite element model numerical analysis method can well simulate the mechanical state of pavement structure under load.(3)The creep characteristics of asphalt mixture on road surface are simulated by using the time hardening creep model of Abaqus finite element software.The moving wheel load is simplified as a double wheel rectangular uniform load under the action ofstandard load BZZ-100.At the same time,the structural model of combined base course long-life pavement is established,and the influence of the thickness and modulus of each structure layer on the mechanical properties of pavement is analyzed systematically.(4)Through orthogonal experiment,the combination of adhesive layer,base course and bottom base of composite base asphalt pavement structure is analyzed,the influence factor of structure layer thickness is optimized,and the primary and secondary priority is determined.