Computational investigation on surface water distribution and permeability of porous asphalt pavement

Abstract

This paper used the finite element method to analyse surface water distribution characteristics on porous asphalt layer under unsaturated seepage, and further compared the critical rainfall intensity of porous asphalt pavements with different design parameters. In this study, the Richards equation was used to describe the unsaturated seepage, and the results were validated with experimental data. The results show that when the water accumulates on the pavement surface, it would firstly emerge at the lowest level of pavement along the longitudinal direction, and then spread along transverse and longitudinal directions. The water depth has no remarkable difference along the longitudinal direction while it differs a lot among different transverse positions. The distribution of surface water depth was analysed and the correlation between the surface water coverage in the transverse direction and the rainfall intensity was established with high R-square values. For pavements with different geometries, the porous layer thickness has the most remarkable effect on the critical rainfall intensity of porous asphalt pavements.