Mechanical and Environmental Evaluation of Lime-Brick Dust Modified Asphalt for Flexible Pavements

This research explores the feasibility of incorporating a 1:3 lime and brick dust blend—derived from the core components of traditional Khorasan mortar—as a modifier in hot mix asphalt (HMA). The additive was introduced into the conventional aggregate-bitumen mixture by replacing fine and filler aggregates at a rate of 2% of the total aggregate mass. Its influence on the performance of the wearing course in road pavements was analyzed through a comprehensive set of laboratory experiments. These tests assessed key parameters, including air void content (Pa), optimum bitumen ratio, voids in mineral aggregate (VMA), voids filled with asphalt (VFA), bulk specific gravity (Gmb), Marshall stability and flow, indirect tensile strength, and wheel rutting depth, to evaluate durability, flexibility, and resistance to deformation. The findings indicated that the modified mixture outperformed conventional blends, significantly improving the long-term durability of the pavement surface. Furthermore, considering the reuse potential of industrial waste bricks, the lime-brick dust mixture emerged as an environmentally sustainable and viable additive for road pavement applications.