Experimental evaluation of eco-friendly asphalt mixtures with recycled fine aggregates and steel slag

This study explores the benefits of using of the recycled concrete aggregates (RCA) and steel slag aggregates (SS) in asphalt concrete mixtures. The mechanical parameters, like Marshall stability, tensile strength, moisture resistance, resilient modulus, rutting and fatigue resistance are evaluated. The crystalline structure of steel slag (SS) enhances particle interactions, with primary elements like calcium, silicon, and iron which contributes significantly in improving asphalt mixture performance in terms of moisture resistance, stiffness, fatigue life, and rutting resistance. The asphalt mixture (named as FAFRSS) with the fine aggregates and fillers being substituted by recycled fine aggregates and the steel slag respectively, has outperformed all other asphalt mixtures from the point of views of Marshall's performance parameters. The FAFRASS mixtures demonstrated an improvement in moisture susceptibility by 15%, resilient modulus by 16.1%, rutting resistance by 37.2%, and fatigue life by 29.2%, when compared to control mixtures. The grey relational analysis also indicated that the FAFRASS mixture outperformed all other asphalt mixtures. Regression analysis has demonstrated the impact of RCA and SS inclusion on the performance of the mixture with strong coefficient of determination values of 0.89, 0.78, and 0.86, with the experimental results. In all, this experimental research study established the promise of using RCA and steel slag in the asphalt mixtures as beneficial from the points of view of eco friendliness and performance.