Adhesive Behavior And Pavement Performance Of Asphalt Mixtures Incorporating Red Mud As A Filler Substitute

With the massive exploitation and utilization of no-renewable natural resources, good-quality road building materials has been becoming scare and it is an urgent demand to explore and develop alterna-tives. This study investigated feasible approaches of using red mud as a filler substitute to replace lime-stone powder in asphalt mixtures. In order to elaborate its influence on adhesive behavior, surface energy components of various fillers, base bitumen, the powder-bitumen interface and the aggregate-asphalt mastic interfaces were calculated and characterized. The mechanical properties of asphalt mastics and asphalt mixtures were assessed by using Quality Control Test (QCT), Hamburg Wheel Tracking (HWT) test and Simple Performance Test (SPT). Referring to the thermodynamic theory, the adhesive performance of the red mud-bitumen interface can be improved by the addition of hydrated lime or Portland cement and the moisture resistance of the aggregate-asphalt mastic bond can be enhanced. It was found that incor-porating the red mud can improve the stiffness and the elastic recovery of asphalt mastic, which in turn had a potential to improve the high-temperature performance of the corresponding asphalt mixtures. Regarding to pavement performance, replacing limestone powder by red mud improved the rutting resis-tance of asphalt mixtures and the moisture resistance can be enhanced by incorporating a certain amount of hydrated lime or Portland cement. (c) 2021 Elsevier Ltd. All rights reserved.