Research on morphology and distribution characteristics of clogging particles in permeable asphalt mixture

The deposition of clogged particles inside permeable asphalt mixture can cause the failure of its permeability. The morphology and distribution of particles are important factors affecting particle deposition. Therefore, the clogging mechanism of permeable asphalt mixture can be further clarified by studying the morphology and distribution characteristics of clogging particles. Five types of permeable asphalt mixtures with different gradations were prepared, and clogging tests were conducted under constant head control mode. Digital microscopy and image processing technology were used to analyze the shape characteristics of deposited and outflow particles. Combined with computer tomography technology, the distribution law of clogging particles along the depth direction of the specimens was analyzed. The results showed that during the clogging process, the mass change of outflow particles varied depending on the size of the clogging particles. The shape index and angularity range of the outflow particles are small, and when the particle size is small, the shape of the outflow particles is greatly influenced by the shape index and angularity of the original particles. When the filling degree of fine aggregate in the permeable asphalt mixture was high, particles with strong rolling ability would become outflow particles. The shape of particles and the filling degree of fine aggregate are important factors affecting the permeability performance of permeable asphalt mixtures. This study provides a reference for a deeper understanding of the clogging mechanism of permeable asphalt mixtures.