Study on Vehicle Speed in Pore Water Pressure of Rigid Pavement Base Using Poro-Elasticity

Abstract

Water in pavement is a major contributor to pavement failure. Fine aggregates are pumped out near the joint of rigid pavement and cause the erosion of the base layer. In order to analyze the phenomenon, a two dimensional model using Finite Element Method (FEM) and Porous elasticity theory is developed to calculate the pore water pressure development in the base layer underneath joints. The model contains three parts, two cement concrete surface plates separated by a joint gap and a base layer with relatively small stiffness and large permeability. The constitutive behavior of porous medium material used in the model is introduced. Nodes along the depth direction of the base layer underneath the joint are analyzed to investigate the erosion of the base. Distributed loading is applied at the part area near the joint to simulate vehicle passing through the rigid pavement surface. Excess pore water pressure along the depth caused by external loading are calculated. The influence of vehicle speed on the base material is analyzed by adding a tire contacting with surface of the cement concrete. The results of the study show that vehicle speed does not only influence the magnitude but also the dissipation of the pore water pressure.