Enhancing Asphalt Pavement Sustainability: Low-Carbon Sulfur Modifiers & Reclaimed Asphalt Impact

Abstract: The asphalt industry faces significant challenges, including the need for more sustainable and longer-lasting pavements due to high environmental impacts and production costs. In line with this, modified binders such as rubber, charcoal, waste cooking oil, and others have shown promise in extending the lifespan, resistance to deformation, and durability of asphalt pavements. Additionally, there is a lot of interest from the government and industrial sectors in using recycled and environment-friendly materials to reduce the carbon footprint and environmental impact of producing asphalt using traditional methods. This study examines the merits of using a low-carbon modifier containing sulfur polymer in the conventional hot mix asphalt mixture containing 25% reclaimed asphalt pavement (RAP). The modifier was introduced at 10 and 20% by the total weight of the asphalt binder representing an asphalt mixture with 9.62% and 19.03% reduction in CO2 equivalent compared to typical asphalt binder. The Indirect Tensile Cracking test and Hamburg Wheel Track test were employed to examine the fracture and rutting resistance of the resulting mixtures, respectively. Extended thermal aging and UV aging were applied to study the effect of long-term aging on each scenario. Aging conditions included oven aging following NCHRP (Report 973) and UV aging following (Rajib and Fini, 2020 ). The study results showed that introducing the modifier led to less reduction in resistance to aging as measured by fracture resistance and rutting durability compared to the control scenario while also reducing the carbon footprint of the mixture by up to 20%.