The use of mixed waste recycled plastic and glass as an aggregate replacement in asphalt mixtures

Abstract

One of the major problems with landfills is that they contain a large amount of solid wastes. Waste plastics and glasses contribute greatly to this problem, and these materials need to be managed or recycled to extend the life of landfill sites. Hence, this study was conducted to investigate the feasibility of using these waste materials in asphalt mixtures for pavement applications. Various types of recycled waste plastics and glasses were selected for this study and the mix containing these materials was designed by the Marshall method. Three types of glass were used: bottle glass, liquid-crystal display (LCD) glass, and sheet glass. In terms of the total weight of the asphalt mixtures, approximately 5% constituted of recycled materials used as an aggregate replacement. In this study, asphalt mixtures were aged in the laboratory to simulate the site conditions of short-term and long-term ageing. After the ageing process, samples were tested for asphalt mixture performance characteristics in terms of the following parameters: Marshall Stability and Flow, Marshall Quotient and resilient modulus. It was found that the replacement combining 1% recycled plastic and 4% recycled glass shows almost similar and satisfactory results compared to the control sample for all tests. Therefore, recycled plastic and recycled glass, when optimally blended, can be considered feasible to be used as an aggregate replacement in asphalt mixtures for flexible road pavements.