Plastic waste in road construction - a path worth paving?: application of dry process in South Asia
As global plastic waste continues to grow, the global community is coalescing to reduce plastic waste. Some stakeholders are also exploring new options to use plastic waste as partial substitute for raw material. The use of plastic waste as a bitumen modifier in road construction, referred to here as ‘plastic roads’, is one option being explored. Reviewed the scientific literature, news articles, and patents; conducted a cost-effectiveness analysis; and interviewed representatives from private companies and independent, scientific researchers to determine the existing knowledge gaps regarding the (1) technology feasibility, including engineering performance; (2) environmental issues; (3) occupational health; (4) economic viability; and (5) industry standards surrounding plastic roads. We found that many companies are starting to implement or pilot this technology worldwide though key gaps in engineering performance, such as cracking resistance, remain. The environmental issues reviewed also have research gaps, including the generation of hazardous air pollutants during production; microplastics and nanoplastics generation during use; and leaching of additives from plastic waste during use. Industry standards for the use of plastic waste in road construction are lacking. In addition, there is prevailing uncertainty in the economic viability of the technology. As a result of these key research gaps, the Ways Forward section presents a roadmap for short- and longterm research priorities.