Research On Water Damage Behavior And Mechanism Of Asphalt Pavement

The water damage to the free way asphalt pavement has been very common in both southern rain-fed areas and northern dried areas. It is nothing new that loose road surface, potholes, slurry pump, net crack, common frog tank and other damage induced by the inchoate water damage appear on the road at an early stage, which severely reduce service level and service life of the road, and cause tremendous damage to the national economy. Therefore, in view of the common characteristics of water damage in our state, it has great theoretical and practical significance to carry out the research of water damage behavior and mechanism on asphalt pavement, to search how water affects the adhesion of asphalt mixture, the flowing water breaks asphalt mixture, and water damage impacts the mechanical properties of pavement structure.In the thesis, and experimental method of asphalt membrane was designed and carried out to test the osmotic time of asphalt membrane at different water temperature, and the relationship during asphalt membrane thickness, water temperature and the osmotic time was built up, and then a conclusion about the water penetration rate in asphalt, modified bitumen and ageing asphalt at different temperature was obtained. By the porous media theory and the fluid dynamics software FLUENT, a simulation was carried out to analyze the inner flow pressure, velocity and direction distribution in the pavement after high-pressure water produced by wheel acted on different porous asphalt pavement. Except for the conventional hydrostatic test, dynamic water washing fatigue test and dynamic water seepage test of asphalt were carried out through the laboratory equipment dynamic water washout test apparatus and dynamic water permeability test apparatus designed by our research group, to study the hydrostatic and hydrodynamic erosion damage of asphalt. From the perpetual pavement design idea of SHELL and AI method, a simulation of the mechanical response in the pavement structures after different degrees water damage was calculated by the finite element analysis software ANSYS. In the simulation, an research of water damage extent was conducted for different mechanical index, studying the order of the inner stress, strain, displacement variation of the pavement after it suffered the water damage in different depths, and then an equivalent analysis on the depth of the water damage and the vehicle load was taken. Otherwise, relying on the paved test road on Hebei section project of Qing-Lan free way, the results of laboratory study were verified.