Cement Kiln Dust as Substitute Fillers for Hot Mix Asphalt

To reduce construction costs, eliminate environmental issues, and protect natural resources, waste and by-product materials are frequently substituted for raw components in asphalt mixtures. This study investigates the feasibility of employing cement kiln dust (CKD), which is abundantly available in various regions of Yemen, as substitute hot mix asphalt filler (HMA) for conventional fillers. A traditional filler, basalt filler (BF), was partially and totally replaced at different percentages of CKD with 25%, 50%, 75%, and 100% by weight of fillers. The evaluation of the planned HMA was done using conventional mechanical and volumetric characteristics. A total of 15 bituminous concrete mix specimens with bitumen content of 4%, 4.5%, 5%, 5.5%, and 6% were created, and the optimum asphalt content was 5.24 %. The impacts of four different (CKD) samples with filler contents of 25%, 50%, 75%, and 100% by weight were compared with respect to bituminous concrete performance. The outcomes of the experiment demonstrated that CKD may substitute 75% of the BF at a bitumen content of 5.24%, 13.76 KN Marshall stability value, 4.02% air voids, 75 % VFB, 2.370 g/cm3 bulk density and 2.57 mm flow. Therefore, incorporating CKD as fillers in HMA is a sustainable solution that enhances performance, durability, and environmental benefits in road asphalt construction.