Study on the clogging pattern of multi-graded microparticles in porous asphalt concrete

Abstract The current research on the blockage law of porous asphalt concrete (PAC) is mostly focused on the macroscopic level, which cannot reveal the decay mechanism of the percolation function of porous asphalt pavement during micro-particle blockage, especially the change law of permeability coefficient. In this paper, the key factors affecting the percolation and clogging characteristics of PAC are analysed at both macroscopic and detailed levels, and the internal void characteristics of PAC and the migration law of clogging particles are quantified. In this experiment, porous asphalt concrete specimens with 15–25% porosity are used to analyse the influence law of different factors on the percolation coefficient and to construct a clogging prediction model under different clogging conditions. CT scans were used to analyse the void characteristics of PAC before and after plugging and cleaning when wind-accumulated sand was used as a plugging material, and an evaluation model of PAC seepage plugging analysis based on fine view void characteristics was established. The results show that the permeable concrete specimens under 200 mm water head are severely plugged, and the seepage below 0.283 m/s appears in the later stage of rapid plugging. The plugging degree of pervious concrete specimens with 25% porosity was significantly higher than that of other porosity specimens.