Investigation on preferential path of fluid flow by using topological network model of permeable asphalt mixture

Abstract The void structures in permeable asphalt pavements are capable of creating space for fluid flow, and the preferential paths of fluid most significantly impact its flow features. In the present study, the aim was to investigate the preferential path of fluid flow using topological network model of permeable asphalt mixtures. Permeable asphalt mixtures were produced in the laboratory, and their internal structure images were captured with the computed tomography. To eliminate the interference of noise and defects in the image, reasonable image processing methods of image de-noising and defect processing were identified. The Otsu method and three-dimensional reconstruction technology were employed to build the three-dimensional structure of the voids. The void contents calculated in the experiment were adopted to verify the feasibility of the void reconstruction. On that basis, the topological network model of the void was further built by morphological processing. Subsequently, Dijkstra algorithm was adopted for comparing the flow resistance of different paths in the topological network, as well as for the determination of the preferential path of flow. The computational fluid dynamics model was employed to verify the feasibility of the preferential flow path by analyzing the distribution rules of flow velocity and streamline of fluid.