Study On Mechanical Analysis Of Asphalt Pavement Based On Measured Load And Anisotropic Properties

At present, the asphalt anisotropy studies suggest that perpendicular to compaction direction of the material properties is the same with the two directions of the horizontal plane and there are significant differences in vertical and horizontal direction, which is assumed to be cross-anisotropic. However, it is pity that the degree of influence of anisotropic properties of asphalt mixture in pavement design and analysis is not well understood. The theoretical basis of design for asphalt pavement in our country is the theory of linear elastic system based on isotropy. The simplified method is difficult to well reflect the basic characteristic of asphalt mixture, which makes the theoretical analysis and calculation results not consistent with the actual situation.At first, in order to investigate the influence of anisotropic characteristics of asphalt mixture on its reaction to the wheel load, finite element method is adopted to calculate the pavement stress caused by the measured non-uniformly distributed tire load. The orthotropic model in the software ANSYS is used to simulate the characteristic of cross-anisotropic. The stresses introduced by the tire load mentioned above acting both on the vertical and horizontal directions, including stress of three directions, shear stress and strain of three directions, making analysis and evaluation has been compared. The results that different cross-anisotropic coefficient has made the mechanical response of asphalt pavement structure different has been showed.Then, dynamic modulus as object will be chosen in the paper to clarify the actual structure of the asphalt pavement in a different direction modulus ratio of exactly relationship, that is to say what exactly the value range of cross-anisotropic coefficient. Combined with the existing research results, a relatively small size of hexahedral specimen in dynamic modulus has been developed in this paper which analyzing the rolling forming of asphalt mixture in three different directions modulus. Test result shows that the dynamic modulus in horizontal plane of longitudinal and transverse directions are both substantially the same while the vertical plane of the dynamic modulus is 1.2 to 1.5 times the horizontal plane.In the end of this paper, dynamic modulus and measured cross-anisotropic coefficient are the input parameters and the mechanical response of asphalt pavement has been recalculated. By calculating the result shows that the maximum tensile strain in three directions will increase with the rise of temperatures and the strain is greater than the value of the mechanical response of isotropic assumptions.