Development of a Plastic Waste-Modified Asphalt Model for Sustainable Road Construction

Plastic bag waste presents a significant global environmental challenge due to its single-use nature and long-term persistence in ecosystems. Global plastic production reached 413.8 million tons in 2023, growing at an average rate of 4% annually, yet less than 10% is recycled. In Thailand, over 2.76 million tons of plastic waste were generated, with only 0.5 million tons reused or recycled. The remainder is typically landfilled or incinerated, exacerbating environmental and health issues. Despite ongoing government campaigns, the convenience of single-use plastics continues to impede public behavioral change, resulting in growing waste accumulation. Current recycling efforts, largely focused on reprocessing plastics into pellets for industrial use, face operational limitations, particularly in sorting and processing non-commercial plastic waste. This study explores an alternative approach through the Plastic Waste-Modified Asphalt Model, which incorporates non-commercial plastic bag waste into asphalt cement at a 25% weight ratio. Engineering assessments indicate that the modified asphalt mixture improves road stability by up to 30% compared to conventional standards. The model was piloted in four national park communities across Thailand, covering 9.80 kilometers (29,387 m²) of road. The initiative diverted over 30,010 kilograms of plastic bag waste from landfills and enhanced community awareness of plastic pollution. The project demonstrated that value recovery from non-commercial plastic waste is both feasible and impactful. The Plastic Waste-Modified Asphalt Model offers a scalable, sustainable solution to plastic waste management, contributing to environmental protection and community well-being while addressing pressing waste disposal challenges.