Research On Shear Resistance Of Asphalt Pavement Structure Based On Strain Energy Theory

Rutting has become one of the main diseases that affect the normal service of asphalt pavement in China. Although many road workers have carried out lot s of research and obtained some achievements in these years, the rutting diseases of asphalt pavement has not been solved. So it is necessary to carry on the research under new strength theory and failure criterion that accorded with the actual characteristics.This paper puts forward a new idea and method for the rese arch on shear resistance of asphalt pavement based on strain energy theory by mechanical analysis and theoretical research. Firstly, elastic layered system program was used to establish the mechanical analysis model of asphalt pavement structure. Then the general rules of distortional energy, dilatational energy, principal stress and shear stress in asphalt surface course to the base course could be gained. The result shows that the upper course is the main anti-rutting region, and the thin layer area near surface under the vehicle load has a great majority of strain energy. The ratio of distortional energy to strain energy is very high which means the asphalt mixture at this position bears most deformation action. This action is easy to result in the shear rheological behavior of the mixture. In addition, the high level of strain energy appears accompanied by high principal stress, shear stress and high stress inhomogeneity.The position of the maximum distortional energy at each depth was selected as research subject to figure out the influence of various factors on the distortional energy. The results showed that the value and response law of distortional energy in the pavements with different basic types are basically the same. Horizontal load is a challenge to the shear capacity of asphalt pavement. The increase of the coefficient of horizontal load can cause the distortional energy increase obviously, the distortional energy concentration phenomenon at the edge of the wheel track is intensified, and the damage effect zone is increased. The distortional energy is sensitive to the elastic modulus of the surface courses, especially the upper course. So materials with good elastic capacity and high elastic modulus is best suited to the upper course, the thin surface layer can be strengthened in special sections. The lack of bonding strength between the surface courses can cause the increase of the distortional energy which result that the asphalt mixture in here is prone to rutting deformation.This paper considered that the application of distortional energy on shear resistance research can break the rigid ideas about single stress regarded as destructive power and Mohr Coulomb theory. It comprehensively considers the effect of complex three-dimensional stress on the formation and destruction of the strength of materials so that the theoretical value and the actual value of the strength characteristics and failure characteristics of asphalt mixture can be more consistent. In the end, the uniaxial compression test was designed to acquire the asphalt mixture’s admissible distortional energy which can evaluate the shear strength. And a new shear checking method based on distortional energy was established.