Evolution of water migration in porous asphalt due to clogging

Abstract

Porous asphalt is a commonly used material for permeable pavement. However, porous asphalt will inevitably result in void structure clogging and affect its drainage function in the road service period. Most studies focus on macroscopic permeability but ignore microscopic seepage behavior in void structure, which is unfavorable for the understanding of the change in the permeability of porous asphalt. In this study, we described the microscopic water migration of the porous asphalt with the seepage depth, seepage velocity, and seepage path, and clarified the void structure evolution and the water migration characteristics variation during the clogging. On this basis, we explored the impact of the size of clogging particles and the void content of porous asphalt on the variation of water migration. The data demonstrate that water migrates and branches along the void structure of porous asphalt under the action of inertia force. The deposition of clogging particles in the void hinder the migration of water and restrict the water distributary. However, the clogging process does not affect the dominant effect of inertia force on water migration. Water migration is more impeded by small particles due to their more significant water absorption effect. The increased void content of porous asphalt can reduce the effect of clogging on the void structure. This research can help us understand the evolution of water migration characteristics at a micro-level.