A Laboratory Study on Enhancing Asphalt Mixture Properties through Dry Mixing with High-Dose Multilayer Plastic Packaging Pellet Additives

Abstract

Flexible pavements are typically vulnerable to distresses caused by fluctuating temperatures and heavy traffic loads, leading to permanent deformation, cracking, and other distress types. Researchers have explored various methods to improve pavement performance, including using thermoplastic additives. One critical area of investigation is using recycled plastic to modify asphalt, which has yielded promising results. This technical paper investigates the potential of using multilayer packaging plastics (MPP) additives in asphalt pavement materials. Integrating MPP into asphalt mixtures can minimize plastic waste, offering a path toward upcycling a valuable waste stream and enhancing pavement performance. By incorporating MPP into asphalt mixtures, both plastic waste reduction and the conservation of virgin aggregate and asphalt cement can be achieved. The MPP stream from the plastic industry can contribute significantly to this endeavor, allowing for a more controlled and superior output than postconsumer plastics. This study analyzed the effects of varying dosages of MPP pellets and asphalt cement (AC) on asphalt mixtures through the dry mixing method. The mixtures included 0%, 2%, 3%, and 4% MPP pellets by the total weight of the mixture, and the AC contents were 5.3%, 5%, 4.7%, and 4.4% respectively. This study utilized various tests to assess the effectiveness of MPP-modified asphalt mixtures, such as the complex (dynamic) modulus test, moisture-induced damage test, indirect tensile cracking test, and Hamburg wheel-track test. The findings demonstrated that incorporating MPP additives into asphalt mixtures can significantly improve resistance to softening at higher temperatures, fracture resistance, rutting resistance, load-carrying capacity, and reducing susceptibility to moisture damage. This research offers valuable insights into integrating MPP additives in asphalt modification, enabling the creation of more durable and safer asphalt pavements. Multilayer packaging plastic (MPP) waste has experienced a significant increase in volume over the past two decades, resulting in notable environmental and economic consequences in Canada and globally. This study explored the potential of the integration of MPP waste into asphalt mixtures as an environmentally friendly solution. MPP-modified asphalt mixtures have been evaluated and examined through a rigorous experimental campaign. The findings showed that MPP-modified mixtures have improved main pavement distresses, particularly rutting and moisture sensitivity. Such improvement increases the service life of flexible pavements and reduces the need for maintenance and rehabilitation operations. In addition to the positive environmental impact, the use of MPP also reduces the cost of modified mixtures and the overall lifecycle cost of pavement.