Developing a Warm Stone-mastic Asphalt Mixture with Construction and Demolition (C&D) Waste.

Abstract: Innovative use of waste materials is the subject of ongoing research. Researchers are exploring the viability, environmental acceptability, and performance of waste materials in highway construction. These studies attempt to strike a balance between the demands of the highway industry for better and more affordable construction materials and those of the society for safe and efficient waste disposal. Saudi Arabia produces around 110 million tons of waste annually, with about 50 million tons of the waste coming from construction and demolition (C&D) waste. This huge quantity of C&D comes from the rapid infrastructure development projects and the demolition of old buildings. Despite the proactive recycling efforts of the relevant authorities, they only recycle or reuse 5% of the waste materials. C&D primarily consists of coarse and fine aggregates, aligning with the asphalt mixture's composition of approximately 95% aggregate and 5% bitumen. Thus, incorporating C&D waste in road construction will reduce the depletion of natural aggregate, reduce the pressure on landfills, and ultimately save the environment. The current study examines the performance of stone-mastic asphalt with C&D waste. We selected stone mastic asphalt as a suitable mixture to withstand the rutting failure of asphalt mixes commonly found in temperate regions like Saudi Arabia. In addition, the mixture was applied as a warm-mix asphalt ( < 130°C) to reduce the harmful impacts associated with hot-mix asphalt (>170°C) on the environment. Findings from this study will help the paving industry to incorporate more waste materials and embrace WMA technology in future road constructions. It will also reduce the number of emissions released to the environment by up to 5 kg of CO2 equivalent per ton of asphalt mixture produced. The outcomes will aid in achieving the goals of SDG12 for responsible consumption and production. It also addresses the SDG 13 goal of reducing global greenhouse gas emissions to avert the 1.5 °C tipping point.