Laboratory evaluation on the effect of clogging on permeability of porous asphalt mixtures

Abstract

Porous asphalt mixture is one of the alternative solutions to increase pervious surface area due to urbanization. The uniqueness of porous asphalt surface textures and internal structures allows the mixture to become a temporary storm-water retention and capable to channel excessive storm water. However, one of the major problems that affect the performance of porous asphalt mixtures is the clogging. Therefore, this study aims to determine the effect of clogging towards the permeability of porous asphalt. A total of 30 gyratory compacted samples were fabricated according to aggregate gradation recommended by Malaysia Public Works Department. The clogging materials were collected from two different location, residential area and major highway. The composition and characteristics of the clogging materials were investigated using Plastic Limit, Liquid Limit and Scanning Electron Microscope (SEM). The permeability test was conducted to investigate the permeability rate of the compacted samples based on different clogging material types, clogging concentrations and clogging cycles. In addition, the compacted samples were scanned using X-ray Computed Tomography to obtain the air voids distribution throughout the samples for comparison. It was found that higher concentration of clogging materials and clogging cycles reduced the rate of permeability. Clogging material collected from residential area has higher tendency to clog the void spaces compared to the one obtained from highway.