Life cycle assessment of hot mix asphalt containing recycled materials: Case study in Australia

Application of recycled materials has considerable advantages in reduction of virgin materials consumption and greenhouse gas emissions. In spite of these encouraging benefits, the utilization of recycled materials, based on limited factors such as emissions reduction or material consumption reduction, may not be advisable to key decision makers since the recycled materials promotion requires a thorough evaluation of this technology as well as the consideration of all critical environmental factors. This paper presents a comparative life cycle assessment (LCA) and cost analysis for asphalt mixtures containing recycled materials including glass and recycled construction aggregate (RCA). The composition of asphalt mixtures selected for this study are determined through a comprehensive laboratory investigation. In order to obtain more realistic results in this LCA, it is assumed that asphalt mixtures are produced in two different asphalt plants located in NSW, Australia which are the largest asphalt plants in Australia. Accordingly, the process parameters and the transport distances are considered as close as possible to real situation. The results of these analyses indicate that the replacement of glass and RCA in asphalt mixtures at optimum content results in a significant reduction in adverse environmental impacts as well as a substantial cost saving in asphalt mixture production.