The use of glass to optimize bitumen absorption of hot mix asphalt containing recycled construction aggregates

Asphalt mixtures containing recycled construction aggregates (RCA) have the problem of high bitumen absorption. This paper characterizes the effects of glass on the bitumen absorption and volumetric properties of asphalt mixtures containing 25% and 50% RCA through laboratory investigation. The materials used in the test program include C320 bitumen, RCA and recycled glass. Three glass contents of 0%, 10%, and 20% in terms of the total weight of fine aggregates are used in the mixture designs for preparing 100 mm diameter specimens containing 0%, 25% and 50% RCA, under 120 gyration cycles. Different types of tests including aggregate specification tests and volumetric analysis tests were conducted on individual aggregates and asphalt mixtures in accordance with Australian standards. The test results indicate that the glass waste can be a viable material for improving the problem of high bitumen absorption of asphalt mixtures containing RCA

Innovations in asphalt mix production incorporating waste materials

Utilization of recycled materials in road construction is not a recent development. However, finding innovative uses for waste materials in road construction is one of the priorities in the pavement industry. In this research, the feasibility of using waste materials including recycled construction aggregate (RCA) as the coarse aggregate, and glass as the fine aggregate in asphalt mix was investigated. Several testing methods and numerical modelling were carried out to assess the mixture performance. Furthermore, Life Cycle Analysis (LCA) model was created using the software GaBi based on process parameters, asphalt mixture parameters, energy and emissions inventory, and impact assessment categories for production of selected asphalt mixtures proposed in this research. In order to obtain more realistic results in comparative LCA model, it was assumed that asphalt mixtures are produced in Boral asphalt plant located in Enfield, NSW, Australia, which is one of the largest asphalt plants in Australia. The process parameters and, particularly, the transport distances were considered as close as possible to the real situation. The results of laboratory investigation, numerical modelling and life cycle analysis indicated that the glass waste can be a viable material for improving the problem of high bitumen absorption of asphalt mixtures containing RCA