Use of Recycled Plastic Materials in Roads and their Potential for Microplastics Release

A total of 3.5 million tonnes of plastics were consumed in Australia for the 2018-19 financial year. 11.5% of the consumed plastics were recycled (locally and exported) while the rest were sent to land fill. With the national ban on plastic exports, alternative methods to deal with waste plastics must be implemented for a sustainable future. In this context the Transport and Infrastructure Council of Australia, which bring together Australian and New Zealand transport ministers, has funded a large research project on recycled plastics in asphalt roads (Austroads Project APT6305). The project is investigating the benefits, methodologies, testing frameworks, and performance-based specifications for incorporating recycled plastics into asphalt. All around the world, road authorities are trying to incorporate recycled materials in roads; but more stringent environmental requirements are coming into place that ask scientists to also evaluate new aspects of these technologies. In fact, although fostering recycling in roads can be seen as an effective measure to reduce the infrastructure’s carbon footprint, there are many aspects that have never been studied before. In the case of recycled plastics, for instance, there are concerns around the possible generation of microplastic particles due to weathering and trafficking. The analysis of the composition of road dust has just started to be evaluated by some research studies and no standards or universal testing frameworks are available yet.