Synergetic Effect of Filler Composition on the Performance of SMA Mixtures

This research study investigates the effect of hydrated lime and granite stone dust as fillers on the performance of stone mastic asphalt (SMA) mixtures. SMA is known for its superior rutting resistance that significantly benefits from the use of appropriate fillers, which improve its structural integrity, rutting resistance, cracking tolerance, and moisture sensitivity. In this study, SMA mixtures were prepared with varying proportions of hydrated lime and granite stone dust, and their impact on key performance metrics was evaluated. Four different filler combinations (7% lime, 7% granite, 2% lime with 5% granite, and 5% lime with 2% granite) were tested using the dynamic creep, Indirect Tensile Asphalt Cracking Test (IDEAL-CT), and modified Lottman test. The results demonstrated that the combination of 5% hydrated lime and 2% granite stone dust provided the optimal balance between rutting, cracking, and moisture susceptibility, thereby making it the most suitable mixture for heavy-traffic road applications. The study’s findings suggest that the careful selection and proportioning of fillers can significantly enhance the durability and performance of SMA mixtures while promoting sustainability through the use of industrial by-products.