The potential use of recycled polyethylene terephthalate (RPET) plastic waste in asphalt binder

Abstract

The current study aims to examine the potential use of recycled polyethylene terephthalate (RPET) plastic waste as a modifier for asphalt binder. Plastic bottles were collected, shredded, cleaned, melted, ground, then sieved. An asphalt binder with a penetration grade of 60/70 was used. The RPET plastic waste was blended with 60/70 penetration grade asphalt binder at five percentages (0, 5, 10, 15, and 20 %, by weight of asphalt binder) using a high shear mixer. To study the physical and mechanical properties of RPET-modified asphalt binders, both traditional and Super pave tests were conducted. The test results showed that by incorporating RPET into asphalt binder, the ductility and penetration values decreased, whereas the softening point and viscosity of asphalt binder increased. Furthermore, the rutting performance of RPET-modified asphalt binder, as presented by the rutting parameter (G*/sinδ), was enhanced by increasing the amount of RPET plastic waste at all testing temperatures. The high-temperature performance grade of asphalt binder was raised by one grade (from 64°C to 70°C) by adding 15% and 20% of RPET plastic waste. On the other hand, the low-temperature performance of asphalt binder, as presented by creep stiffness and m-value, was negatively affected by adding RPET. The low-temperature performance grade of asphalt binder was dropped by one grade (from −22°C to −16°C) by adding RPET plastic waste at percentages of 15 % and 20 %. Moreover, the fatigue cracking performance of asphalt binder, as presented by the fatigue parameter (G*.sinδ), was slightly reduced by adding RPET to the asphalt binder but remained lower than the acceptable Super pave limit (≤ 5000 kPa).