Effects of air voids content on the performance of porous asphalt mixtures

This study evaluates the effects of different air voids content on the resilient modulus, abrasion loss and permeability of porous asphalt mixture. One of the main issues with porous asphalt mixture is having an adequate amount of air voids content for its performance. High air voids content will increase the infiltration rate but reduces its durability and vice versa. Gyratory compacted samples were fabricated at various air void contents i.e. 17.5%, 20% and 22.5% using aggregate gradations adopted from Australian and Singaporean specifications. The samples were tested for permeability, resilient modulus and abrasion loss. From the analysis, it was found that the increase in the voids content improves the permeability but adversely affects the resilient modulus and the mixture's performance under abrasion. The resilient modulus and abrasion loss show similar pattern at low air voids content where no significant difference between both mixture types but at high voids content, finer compositions shows to be more durable. Therefore, it can be concluded that the air voids content influences the performance of porous asphalt mixtures