Using Marble Dust from the Wadi Al-Shati Area as a Filler Material in Hot Asphalt Mixtures

Abstract

Urban expansion and industrial activities are associated with a significant increase in solid waste generation, which has become an environmental concern due to the difficulty of safe disposal and the high cost of treatment. Consequently, many studies have focused on reusing these wastes in various engineering applications, particularly in road construction. This study aims to evaluate the feasibility of using marble dust as a substitute for conventional filler in hot mix asphalt and to investigate its effect on the properties of the mixture in southern Libya. The reference mix was prepared after conducting the necessary tests on the mixture components and determining the optimum bitumen content. The conventional mineral filler content was 5.15% of the total weight of aggregates used in the asphalt mixture. The filler was then replaced with marble dust at different percentages of 0%, 25%, 50%, 75%, and 100% by weight. The results showed that the incorporation of marble dust had a positive effect on most asphalt mixture properties, as it increased density and stability while reducing air voids, with VMA values remaining within acceptable limits. It was also observed that higher replacement ratios (75%–100%) provided the best performance in terms of the balance between stiffness and flexibility. Furthermore, the findings indicated that marble dust can effectively function as a filler material without negatively affecting the performance of the asphalt mixture. It contributed to improved resistance to permanent deformation, reduced permeability, and enhanced internal cohesion, making it suitable for use in the hot and dry conditions of southern Libya. Based on these findings, it is recommended to adopt marble dust replacement ratios ranging from 75% to 100% as a substitute for conventional filler to achieve improved structural and economic performance of asphalt mixtures.