Bayside Mayor, Cr Hanna El Mouallem (left) and RMIT Associate Professor Filippo Giustozzi (right) . Image: Bayside Council
The results of Australia’s largest council-led recycled rubber road project have been revealed and demonstrate “significant promise” for the product in road resurfacing.
The trial involved 12 councils using recycled rubber-modified asphalt mix in their road resurfacing projects. Three councils in the Burwood Council, City of Sydney, and Northern Beaches Council areas undertook in-depth investigations into the material’s environmental impact.
The trial was conducted in 2023 by the Southern Sydney Regional Organisation of Councils (SSROC), RMIT University, Tyre Stewardship Australia, and the Australian Flexible Pavement Association (AfPA) in partnership.
“The calculations done by RMIT University regarding project-level environmental impacts at SSROC councils have demonstrated that incorporating crumb rubber into asphalt roads using the wet method holds significant promise for reducing the total carbon footprint of these roads by up to 30 per cent throughout their service life,” RMIT Civil and Infrastructure Engineering Professor, Filippo Giustozzi said.
“This can potentially offset the environmental impacts generated by new road construction and ongoing maintenance operations, therefore contributing to the decarbonization of the road infrastructure.”
The study found that incorporating recycled rubber into asphalt mixes using the wet method (crumb rubber assimilated into bitumen at high temperature to produce a modified polymer) can reduce environmental impacts during the production and construction phase compared to conventional asphalt. By adding 10 per cent crumb rubber by weight of the total binder (100 grams of crumb rubber to 900 grams of virgin bitumen to manufacture 1 kg of rubbermodified binder) resulted in lower environmental impacts compared to using 1 kg of conventional bitumen, leading to reduced emissions during the construction phase.
The assessment considers existing research that has demonstrated improvements in pavement performance due to rubber-modified asphalt needing fewer maintenance interventions during the service life, consequently reducing environmental impacts (up to 30 per cent) associated with the maintenance phase of the road asset.
It also demonstrated indirect environmental benefits, such as recovering steel from end-of life tyres during crumb rubber production and diverting waste tyres from landfills, which will further decrease greenhouse gas emissions associated with using rubber-modified asphalt.
“This project is a great example of circular economy. Using crumb rubber from end-of-life tyres can help Australia cut down on the more than 450,000 tonnes of waste tyres generated annually,” AfPA technology and leadership executive director Anna D’Angelo said.
“The use of crumb rubber in asphalt increases the performance and durability of the roads while fostering a more sustainable waste-to-resource approach.”
TSA chief executive Lina Goodman said the project underscored the importance of incorporating recycled materials, like recovered crumb rubber, in asphalt.
“(It) demonstrates the value of crumb rubber in asphalt. Not only does it offer performance benefits to extend the roads’ life and increase performance, but crumb rubber also reduces carbon emissions and environmental impacts,” she said.
“Using crumb rubber in roads is a key way Australia can derive value from end-of-life tyres in the circular economy.”
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