The study of the feasibility of using recycled steel slag aggregate in hot mix asphalt

Abstract

Significant growth in the road network around the world has increased the need for pavement materials. The growing demand for producing original asphalt pavements from non-renewable natural resources can deplete natural resources, cause environmental issues, and consume significant amounts of energy. The idea of using waste materials such as steel slag or reusing recycled aggregated of old pavements was evaluated to increase the sustainability of pavements. Rutting resistance, marshall stability, moisture susceptibility, resilient modulus, and fatigue life of slag and conventional asphalt mixtures containing different percentages (0, 25, 50, and 75 wt%) of (Recycled Asphalt Pavement) RAP or slag aggregates were compared to evaluate the mechanical performance of recycled asphalt with slag aggregate, The recycled asphalt mixtures were rejuvenated by 3 or 6 wt% of automobile waste oil. The results showed that slag asphalt had a better performance in all areas. Additionally, replacing the original aggregate with RAP or recycled slag improved marshall stability, tensile strength, and rutting resistance of the asphalt or slag asphalt mixture. Using higher percentages of the recycled aggregate resulted in further improvements. The fatigue life of the recycled samples increased under loading with low strain level when higher percentages of the recycled aggregate were replaced, but it reversed at higher strains. Finally, the results indicated that using recycled steel slag for producing hot mix asphalt could produce a more durable asphalt in comparison to using RAP.