Mechanical properties of stone mastic asphalt containing high-density polyethene: An Australian case

Using stone mastic asphalt (SMA) has increased considerably, mostly due to the improvement in serviceability of pavements. This type of asphalt mix is made with more coarse aggregates than fine aggregates. Therefore, using proper bitumen with a better coating among the aggregates is important. On the other hand, since the population grows, the production of waste materials drastically increases. Therefore, the importance of using recycled materials in other industries has increased every day. One of the most prominent types of waste materials is high-density polyethene (HDPE). HDPE is polymer waste and can improve the performance of bitumen. HDPE can be found in many municipal wastes, such as plastic bottles. Therefore, constructing pavements containing HDPE can reduce waste materials and the cost of maintaining and rehabilitating roads from the improvements of mechanical properties and performances of mixtures. This study aimed to investigate the effectiveness of HDPE on the mechanical properties and performance of SMA. Hence, Marshall properties, maximum density, bulk density, and stability were measured for the mechanical properties. Wheel tracking and four-point bending test were carried out as the performance evaluation of rutting and fatigue resistance, respectively. The results showed SMA mixtures containing 4% HDPE had the best fatigue resistance, while rutting performance was 8% HDPE. The maximum fatigue life and minimum rutting depth were recorded as 157,090 cycles and 1.05 mm, respectively.