Lateral permeability of pervious asphalt mixtures and the influence of clogging

Lateral permeability of pervious asphalt concrete (PAC) plays an important role in the drainage performance of pervious pavements, especially for pavements with an impermeable base layer. The clogging of pores caused by sediment could significantly affect the permeability. To evaluate the influence of clogging on the lateral permeability of PAC, clogging test and permeability test were conducted in this study. The main influencing factors including porosity level of PAC, sediment particle size and gradation were taken into consideration. The test results show that a rapid reduction occurred in lateral permeability with the increase in clogging cycle, especially after the first clogging cycle. The permeable variation was found strongly related to particle characteristics. The permeability of PAC13-I (PAC specimens with an average porosity of 19.2%) easily decreased when large-sized particles of 0.3 - 2.36 mm were used. By comparison, the permeability of PAC13-Ill (PAC specimens with an average porosity of 23.5%) were easily influenced by small-sized particles of<0.6 mm. In addition, the lateral permeability was obviously weaker than vertical permeability for bigger clogging particles. However, long-term lateral permeability may be better than vertical permeability for finer particles in clogging sediments. Overall, these findings are helpful to the design and maintenance of pervious asphalt mixture. (C) 2020 Elsevier Ltd. All rights reserved.