Simulation Test of the Dynamic Water Pressure of Asphalt Concrete

Abstract

The simulation of dynamic water pressure is one of the basic methods that should be researched to improve the resistance of an asphalt mixture to water damage. In this study a test system that generates dynamic water pressure in the voids of asphalt concrete by compressed air was designed. A cylindrical asphalt concrete specimen that had a space on its bottom and was covered with epoxy resin glue laterally was fabricated to orient water flow through the asphalt concrete voids into the established space. Thus the oriented water erosion mode was formed. FEM analysis revealed that the drainage can reduce the pore pressure in the specimen along its depth, indicating that the pore pressure was higher in the semi-rigid base asphalt pavement than in the drainage base asphalt pavement. The test results were as follows. First, the splitting strength of the specimen gradually decreased because of water erosion. Second, powder escaped, shear failure occurred, and the asphalt film was stripped from the damaged surface during the oriented erosion to the specimen at 60 °C, indicating the significant effect of the dynamic pore pressure. Third and last, the asphalt mixture with a void ratio of approximately 8% exhibited minimum resistance to water damage. These phenomena revealed that the method can be used to evaluate the resistance of asphalt concrete to water damage.