Laboratory Evaluation of Sustainable Asphalt Mix Using Bottom Ash and Styrene Butadiene Styrene

Abstract

The increasing demand for sustainable road construction materials has prompted researchers to explore alternative methods for modifying bitumen to improve pavement performance while enhancing environmental sustainability. This research aims to evaluate the effect of using Bottom Ash (BA) as a bitumen modifier along with Styrene Butadiene Styrene (SBS) to enhance the mechanical properties and durability of hot mix asphalt (HMA). The effect on Marshall Stability, Indirect Tensile Strength (ITS), Tensile Strength Ratio (TSR), and rutting resistance was evaluated using a Wheel Tracking Test (WTT). The results showed that using 5% BA and 4% SBS improved the performance of the asphalt. The Marshall Stability value increased by 33.65% compared to the unmodified mixture, indicating a significant improvement in load resistance. While the unconditional value of the (ITS) test increase by 32.46% compared to the unmodified mixture, the conditional value (after water immersion) increased by 54.16% compared to the unmodified mixture, indicating an improvement in moisture resistance. The TSR test results confirmed that the modified mixture achieved a 16.39% increase compared to the unmodified mixture, indicating high resistance to moisture effects. In addition, the (WTT) results also showed a 53% reduction in wear depth compared to the unmodified mix, reflecting an improvement in the resistance to permanent deformations under repeated traffic loads.BA is recommended for use with SBS because it significantly improves the mechanical performance of the asphalt mix. It provides an economical and sustainable solution by using recycled industrial waste, reducing reliance on virgin raw materials, and enhancing the durability of asphalt pavement in the face of harsh environmental and traffic conditions.