Performance enhancement of porous asphalt pavement using red mud as alternative filler

Porous asphalt pavement material is a special asphalt mixture with a void content of 18% or more. The porosity is essential to the ecological functions of porous asphalt pavement, i.e., water drainage, noise reduction, water purification. However, the porous structure of pavement also has caused some structural defects. Rutting, raveling and void clogging hindered its popularization in heavy-load and high-speed field. The major cause of the raveling and rutting is the temperature sensitivity and a lack of adhesion of asphalt mortar, especially under repeated heavy load from vehicles. Firstly, this study prepares six types of asphalt mortar including two types of fillers (limestone powder and red mud) and three filler bitumen ratios (0.3, 0.6, 0.9). Secondly, the rheological properties of asphalt mortar are investigated through Brookfield Viscosity, Superpave high temperature binder criteria G∗/sinδ, Multiple Stress Creep Recovery and Bending Beam Rheometer. Thirdly, this study investigated the effect of filler type and filler-bitumen ratio (FB ratio) on the air void, permeability, adhesion performance and raveling resistance. Finally, Hamburg Wheel Tracking Test and three types of Cantabro Tests (standard, water immersion and aging) are performed to confirm that the raveling and rutting resistance performance of red mud is better compared to the widely used limestone powder. The results indicate that the performance of porous asphalt with red mud filler at 0.9 FB ratio exhibited enhanced performance for raveling and rutting resistance.