Sustainable Solutions for Structural Stability and Waste Management in Pavements

Abstract

The research focus has shifted towards sustainable and eco-friendly pavements due to the rising costs of new materials, dwindling resources, and the increasing problem of plastic waste. Developing countries like Pakistan face challenges in funding the construction, repair, and maintenance of their extensive road networks, mainly due to the disposal of Reclaimed Asphalt Pavement (RAP) from the construction industry and plastic waste. This study aims to address these issues by investigating the utilization of RAP and plastic waste in asphalt pavements. The virgin binder was modified by adding 10% Polyethylene Terephthalate (PET) and two different amounts of RAP (20% and 40%). The modified binder's conventional properties were evaluated through penetration and softening point tests. Moisture susceptibility was assessed using the Indirect Tensile Strength (ITS) test, while resistance against rutting was evaluated using the Hamburg Wheel Tracker Test. The modified binder demonstrated stability up to a temperature of 470°C and improved resistance against rutting. Marshall mix properties were determined and compared to the specifications of the National Highway Authority of Pakistan. Optimum Marshall stability was achieved with 10% Polyethylene Terephthalate (PET) and 40% Reclaimed Asphalt Pavement (RAP), while flow and air voids remained within acceptable limits. The results indicate that incorporating plastic waste in asphalt pavements enhances performance, reduces environmental pollution, and mitigates landfill problems associated with RAP and plastic waste. An Environmental Impact Assessment was conducted, revealing that RAP has a lesser adverse impact compared to virgin asphalt. A cost-benefit analysis was performed, showing that using RAP in pavements can reduce costs by up to 30% for a hauling distance of 5 km.