Effects of deposition states and distribution regularity of clogging substances on pore clogging behaviors of double-layer drainage asphalt pavement

Abstract

To understand the pore clogging mechanism and the distribution regularity of pore clogging substances in double-layer drainage asphalt pavement, the discrete element method (DEM) and computational fluid dynamics (CFD)-DEM were used to discuss the clogging substance distributions and clogging depth development in upper and lower layers under natural deposition and seepage flow. Results indicate that the pore clogging of double-layer drainage asphalt pavement is mainly attributed to the accumulation of small-sized clogging substances centered on the large-sized ones, the agglomeration of various particle-sized clogging substances, and the interference between the sizes of clogging substances and pavement pores. Also, the particle gradation of clogging substance shows a significant effect on its distribution and deposition depth in upper or lower layer under natural deposition and seepage flow. Additionally, the void volume combination and thickness combination between upper and lower layers obviously affect the distribution regularity of clogging substances under natural deposition. The clogging depth of each particle-sized clogging substance is directly proportional to void volume and inversely proportional to thickness of upper layer under seepage flow. Finally, the main clogging substances are mainly concentrated in upper layer under natural deposition and seepage flow, and only fewer small-sized clogging substances are distributed in lower layer. Some small-sized clogging substances are flowed out of the pavement pore under seepage flow, which is difficult to cause the pore clogging. This study provides a reference for the optimization design and maintenance of double-layer drainage asphalt pavement.