文摘
Shear fatigue performance at the interface of asphalt pavement layers was investigated in this study by conducting indoor shear fatigue tests, and the shear fatigue failure mechanism of the tack coat materials and the factors affecting the shear fatigue life were analyzed. The results clearly show that the shear fatigue life of tack coat material is affected by stress level and temperature. The relationship between NfTNfT0 and TT0 was found to be a good power function, and the value of “m” of SBS-modification-emulsified asphalt was calculated by nonlinear fitting. Then, the temperature-modifying methods for the shear fatigue life prediction model as well as the calculation methods for the shear fatigue equivalent temperature of asphalt pavement of interlayer materials were proposed. The axle-load conversion method was established based on the equivalence principle of shear fatigue. The conversion coefficients (b/c) of the ESAL of the three types of tack coat materials were calculated to be 2.43, 2.13, and 2.24. The correction coefficient (K = 95) of the materials’ actual shear fatigue life at the interface of asphalt pavement layers was also determined. The application results indicate that when the tensile fatigue stress and permanent deformation of asphalt pavement are used as the design standards, its contact status at the interface of asphalt pavement layers cannot satisfy the requirements of pavement shear fatigue. Therefore, in the design of asphalt pavement, it is recommended to add the shear fatigue stress at the interface of asphalt pavement layers as the design index. According to the asphalt pavement mechanics analysis and study of the shear fatigue characteristics of tack coat materials, an interlayer design method for asphalt pavement was proposed based on the shear fatigue failure at the interface of asphalt pavement layers, and this provides a scientific foundation for the design of asphalt pavements.
