Use of Recycled Low Density Polyethylene Plastic Waste in Stone Mastic Asphalt

In Singapore, about 1 million tonnes of plastic waste was generated in 2022. It was the largest amount of waste disposed in landfill with only 6% of the plastic waste was recycled. To increase the plastic recycling rate in Singapore, a study was carried out to investigate the use of recycled plastic waste in stone mastic asphalt (SMA) which is commonly used for heavy traffic applications. Previous studies have demonstrated that the recycled low density polyethylene (LDPE) plastic waste can enhance the performance of dense-graded asphalt mixture. This further study aims to evaluate the use of the recycled LDPE in SMA, and thereby expand the use of plastic wastes for road construction applications. Asphalt test samples containing various proportions of recycled LDPE plastic waste were prepared in the laboratory. The results were compared with control samples using conventional Pen 60/70 bitumen. The performance properties were evaluated with respect to different engineering properties including resilient modulus, indirect tensile strength, cracking resistance test and Hamburg wheel-tracking tests.