The strength and environmental performance of asphalt mixtures with recycled concrete aggregates

Recycling of concrete aggregates in asphalt pavement surfacing is a viable solid waste management strategy. This study evaluated the strength and environmental performance of asphalt mixtures containing different proportions of Recycled Concrete Aggregates (RCA) for road pavement surfacing. Laboratory experiments and environmental life cycle assessment were conducted for different asphalt mixtures. The mixture was evaluated based on their stability/Global Warming Potential (GWP), resilient modulus/GWP, and Indirect Tensile Strength (ITS)/GWP ratios. The mixture containing 40% coarse RCA was judged to be the most efficient based on its highest resilient modulus/GWP and ITS/GWP ratios of 108.30 MPa/kg CO2 eq and 11.75 kPa/kg CO2 eq, respectively. These values are about 9% and 4% higher than the control values for the two indicators, respectively. The study recommended 40% partial replacement of granite with RCA in Stone Mastic Asphalt for optimum strength and environmental impact.