DEM-CFD simulation on clogging and degradation of air voids in double-layer porous asphalt pavement under rainfall

摘要

With the increasing awareness of the environmental challenges, the porous asphalt pavement has shown greater interests in terms of stormwater management, underground water quality improvement, mitigation of heat-island effect, and reduction of traffic noise. However, these environmental benefits will deteriorate once the porous asphalt pavement is clogged by particles. The aim of this study was using the discrete element method coupled with computational fluid dynamics (DEM-CFD) model to numerically reveal the clogging development in the porous asphalt pavement under rainfall, considering the climate, air voids of the pavement, flow rate, mass of clogging materials, and pavement structure. The degradation of air voids in the double-layer porous asphalt pavement under gravity and/or rainfall was predicted. The results demonstrated that the clogging evolves through four stages, namely rapid clogging, slow clogging, partial recovery, and clogging stability in the pavement under rainfall. The effects of the climate, air voids, mass of clogging materials, and pavement structure on the clogging development are significant. Flow rate imposes negligible effect on clogging evolution in the porous pavement. All factors induce impacts on clogging rate and the distribution frequency of clogging particles in the pavement. Additionally, after clogging, air voids in the double-layer porous asphalt pavement is reduced by 0.8% in the sunny days and 0.55% in the rainy days. The findings in this study contribute to the design and maintenance of the double-layer porous asphalt pavement with superior environmental benefits.