Dynamic Pore Water Pressure Driving Mechanism Research Of Asphalt Pavement Moisture Damage

At present the moisture damage is recognized as the top early damage mode of asphalt pavement, but its mechanism still is not very clear. Previously people often study asphalt membrane how to strip in static water from the view of physical and chemical. But the studying of the drive function and mechanism of dynamic pore water pressure and securing force under wheel load is not in depth. Although the formers did some research on the moisture damage development regular and the faction of water, much of that is base on experience and not on the quantitative study. Therefore, under the premise of rationality in hypothesis, we seek rational analysis method. Comprehensive consider the main factors of moisture damage such as the repeated wheel load and hydraulic drive function of water, come up with the mechanical analysis of moisture damage model. Compared and analyzed the theory and experiment results to study the mechanism of moisture damage and Put forward effective prevention measures of asphalt pavement moisture damage. All of these are very important.This subject studied the drive mechanism of dynamic pore water pressure and scouring force using advanced test technology and mechanical analysis method. Developed the sensor for measuring the dynamic pore water pressure and dynamic stress, which is resistant high temperature in the road paving period. Though measuring the dynamic pore water pressure and dynamic stress, study the regular of dynamic pore water pressure and dynamic stress to reveal the fluid-solid coupling dynamics mechanism of asphalt pavement moisture damage. Based on the Biot dynamic consolidation theory, designed two numerical simulation methods reflecting mobile effect of wheel load, and using the methods to numerically simulate the regular of dynamic pore water pressure under several different conditions. Considering the effect of surface water pressure, wheel load, speed of the vehicle, frictional force and pavement structure, research the restrain effect of drainage base course from the view of fluid-solid coupling. At the same time we also studied the effect of the water in aggregate in the production process of asphalt mixture. Internal moisture damage is divided into two process include asphalt membrane dissection and the broken, using asphalt viscoelastic theory and gas expanding theory established their theory model. And establish theoretical foundation for the research of internal moisture damage.Spot test and numerical imitation results show that the saturated asphalt pavement has a positive move water pressure and vacuum negative pressure under wheel load. In this process the repeated scouring of water accelerated the asphalt pavement damage. Through the comparison of two kinds of pavement structure, found that the peak of dynamic pore water pressure and peak of scouring force significantly reduced after set drainage base course. When moisture exists in the pavement structure, both high vehicle speed and overloading will accelerate the reduction of pavement performance. The pavement dynamic deflection dose not increase though the modulus of permeable base is low. Little vehicle overload can induce larger dynamic deflection thus causes larger pavement deformation even plastic damage. Therefore the drainage base course can inhibit the moisture damage. Studied the internal moisture damage through theoretical analysis and set failure model.