Water Erosion Behavior Of Drainage Base Of Asphalt Pavements Under Vehicle Load Action

It becomes the main method to reduce water damage that the drainage system is installed in the pavement structure to exclude water causing various damages. Plenty of researches have been conducted in the drainage base in recent years in China, mainly focused on material performance of drainage base, drainage performance and mechanical performance. Some scholar have done mechanical analysis on the asphalt pavement with drainage base, however, the water on the surface of pavement have great impact on the pavement structure. It is believed in this paper that the influence of saturation of pavement is of necessity to be considered in the study of pavement with drainage base.Finite element model is used in this paper to analyze, and the main research results are in the followings:(1) ABAQUS finite element software is applied to establish the finite element model of asphalt pavement in saturation. The stress-strain properties of asphalt pavement structure both in the condition devoid of water and saturated are compared and analyzed to study on the effect of saturation water from pavement on asphalt pavement.(2) It can be found by comparing stress-strain properties of ordinary pavement and pavement with drainage base in saturation condition that, the modulus of drainage layer is low in the asphalt pavement with drainage base, which causes that the stress is worse than that of ordinary pavement. The installment of drainage base in the pavement can not only reduce the concentration of pore water pressure in the surface of pavement, but also can decrease the pore water high pressure occurred in the surface of pavement to some extent, but it cannot solve the problem completely that the pore water pressure is too high in the surface of pavement. The installment of drainage layer can lower damage action of pore water pressure on pavement structure.(3) Pavements with three different types of drainage layers are compared and the forces of pavement structure with different drainage layer are different. It is by compared that the force of drainage pavement built of crush-stones stabilized with cement is comparatively good, and the water erosion is low. But pavement structure with drainage layer built of graded crushed-stone, especially the base, suffers water erosion worse than the other two drainage layers. Because asphalt-treated permeable base (ATPB) is not sufficient in mechanical property compared with AM, and its durability is bad, it is suggested that the AM should be as drainage layer of pavement under the condition of meeting the requirement of pavement drainage.(4) Based on the water damage mechanism of pavement structure, the water erosion tester and experimental method are designed to conduct water erosion test on pavement material. In addition, a water erosion resistance index is found to evaluate the erosion resistance of asphalt mixture.