Almost half of the Northern Territory’s end-of-life tyres are sent to landfill and the rest are exported interstate for recycling, but a Charles Darwin University (CDU) study is turning that waste into stronger, more sustainable roads designed for the Territory’s extreme conditions. The project is a partnership between CDU and the NT Government’s Department of Logistics and Infrastructure.

The research is examining how roads made with bitumen and asphalt modified with shredded tyre waste and recycled plastics perform compared to traditional materials. Study lead author and CDU PhD candidate Ramin Shahbazi says materials developed for cooler climates often fail to withstand the NT’s heat and UV exposure.

“The hot weather up here means the long-term effects of ageing roads cause different chemical reactions within the pavement, which makes the road harder or more brittle and leads to damaged roads,” he says.

“We’re working to match the performance of regular pavement materials by using recycled materials, but I think there’s potential we could surpass that performance.”

Ramin says the approach could also deliver more cost-effective construction and maintenance outcomes: “Paying for an expensive polymer just to meet the traffic and weather conditions of Territory roads is like adding an environmental cost to the infrastructure’s overall price tag.”

He hopes the project will help standardise the use of recycled materials in infrastructure and encourage investment in local recycling facilities. Tyre Stewardship Australia’s 2023-24 annual report shows 500,000 tonnes of tyres reach their end-of-life stage nationally each year, highlighting the scale of the opportunity.

“Investing in the specific recycling facilities for these materials will then contribute to the circular economy in the Territory,” Ramin says.