A Study on Effect of Addition of Steel Slag to Stone Matrix Asphalt (Grade-2) Using VG-30 Grade Bitumen

Abstract: The thesis investigates the performance of Stone Matrix Asphalt (SMA) mixes using VG-30 binder with varying proportions of steel slag and cellulose fibers. Comprehensive Marshall Stability and draindown tests were conducted to evaluate the impact of these additives on different parameters, including stability, air voids, flow values, and binder retention. For conventional SMA mixes, optimal performance was achieved at 6.2% binder content, yielding peak stability (10.57 kN) and acceptable voids in mineral aggregate (17.08%–18.49%) while ensuring durability and resistance to deformation. Incorporating steel slag significantly improved performance, with the best results observed at 20% slag content and 6.2% binder. Stability peaked at 12.39 kN, and air voids were reduced, demonstrating improved compaction and binder distribution. The addition of cellulose fibers further enhanced binder retention, reducing draindown to a minimum of 0.08% at 0.35% fiber at 6.2% binder content. Optimal performance with cellulose fibers was noted at 6.2% binder, ensuring a balance between stability, flow values, and durability. Higher fiber and steel slag content enhanced tensile strength and moisture resistance, as indicated by high TSR values (above 0.94). These findings highlight the effectiveness of steel slag and cellulose fiber in enhancing SMA properties, offering sustainable and durable solutions for heavy-duty pavements. By optimizing binder, slag, and fiber content, the study provides a framework for improving SMA mix performance under varying traffic and environmental conditions