A sustainable approach for road pothole repair using waste plastic bottles and aggregates

Purpose This study explores a sustainable method for repairing road potholes using a composite material made from waste polyethylene terephthalate (PET) plastic bottles and local aggregates. This study aims to address plastic waste management challenges and provide a cost-effective and durable road maintenance solution. Design/methodology/approach PET bottles were collected, sliced, cleaned and melted at 280°C. Coarse and fine aggregates were characterized per Central Materials Laboratory (CML) standards. Mixtures with varying PET and aggregate ratios were prepared, molded into specimens and tested for mechanical properties following ASTM D1559-89 and ASTM D3967 standards. Findings The optimal mixture (30% PET, 30% sand and 40% gravel) outperformed conventional asphalt mixtures, achieving a Marshall stability of 59.78 kN, indirect tensile strength of 5,909 kPa and a resilient modulus of 36,145 MPa, exceeding Tanzanian road construction standards. Research limitations/implications Although laboratory results are promising, further field trials are needed to evaluate the long-term performance and durability of the plastic-aggregate composite in real-world conditions. Practical implications This solution offers a cost-effective, sustainable option for road pothole repair, especially in developing countries with budget constraints and significant plastic waste. Social implications By repurposing plastic waste and providing durable road maintenance, this research supports the United Nations' SDGs, promotes environmental conservation and fosters economic development through improved transportation infrastructure. Originality/value This innovative method uses waste plastic bottles as a standalone repair material, eliminating petroleum or cementitious binders and promoting a circular economy. This approach utilizes waste streams, thereby reducing maintenance costs and addressing plastic waste issues.