New roads mixed with recycled plastics at ten sites across Victoria will demonstrate a viable circular-economy solution to the nation, experts say. The RMIT University-led project – supported by the Australian Research Council, Austroads and 10 Victorian councils – will incorporate recycled plastic from consumer and industrial waste, including notoriously stubborn soft plastics, into asphalt as a performance enhancer.
With Australians generating 2.6 million tonnes of plastic waste each year and landfill space expected to reach capacity by 2025, this project is helping to address an urgent challenge. Project lead, RMIT Associate Professor Filippo Giustozzi, said the team will also produce best-practice guidelines on the use of recycled plastics in asphalt roads.
“These guidelines will enable local governments, which control 80% of the nation’s roads, to begin widescale adoption of this innovative recycling solution,” said Giustozzi from RMIT’s School of Engineering.
The City of Melbourne and nine suburban and regional councils will lead the way, each having sections of recycled road up to 900 metres long paved over coming months. The 10 project sites will use an estimated 21,000 kg of recycled plastic, but the potential scale of this solution is considerable given the several hundred thousand kilometres of roads across Australia
“If Australia’s 537 local governments each used a small amount of recycled plastic in the many roads they resurface each year, then nationally we’ll have created a large end-market for recycled plastic,” he said.
Extensive laboratory studies conducted by RMIT for Austroads – the collective of the Australian and New Zealand transport agencies – show these mixes are mechanically, chemically, and environmentally sound.
The team’s latest study, funded by Austroads and published in the international peer-reviewed scientific journal, Science of The Total Environment, found that the recycled plastic asphalt mixtures had 150% less cracking and 85% less deformation under pressure testing than conventional asphalt.
Austroads Chief Executive, Geoff Allan, noted increasing interest in exploring the viability of repurposing recycled waste plastic, and said Austroads was leading ground-breaking work to investigate the most suitable types of plastics for use in roads.
Along with Austroads, the collaboration includes Australia’s leading pavement authorities and specialists, including public works and building bodies, recyclers and contractors. It will be coordinated under the ARC Industrial Transformation Research Hub for Transformation of Reclaimed Waste Resources to Engineered Materials and Solutions for a Circular Economy (TREMS).
Local government areas involved in the project include City of Melbourne, Banyule, Bayside, Moonee Valley, Hobsons Bay, Baw Baw, Latrobe, Casey, Mornington Peninsula and Wyndham.
‘Engineering properties, microplastics and emissions assessment of recycled plastic modified asphalt mixtures’ is published in Science of the Total Environment (DOI: 10.1016/j.scitotenv.2023.164869).