Porous Lane: Old tyres reborn as permeable pavements to save water

The need

Fifty-eight million used tyres are discarded in Australia every year, with less than 10 per cent being repurposed. In addition to this waste problem, urban centres are becoming more densely populated than ever, with flooding and the associated run-off rainwater contaminating precious local waterways and posing health risks to humans and nature alike.

One of the reasons this polluted flood run-off makes its way back to natural water sources is because current road materials are not permeable. Although permeable pavements have been used for decades locally and in Europe, they have mainly used unsustainable crushed quarried rock that requires carbon-intensive processing before use and thus, ironically, continues to contribute to environmental damage.

“Current conventional products are suitable for children’s playgrounds and landscaping,” says Associate Professor Mahdi Disfani, a geotechnical engineer and Head of Research and Development at Porous Lane. “But roads and pavements are everywhere. We need to find a better solution.”

The research

Associate Professor Disfani and his colleague Dr Amir Mehdizadeh, in the University of Melbourne’s Faculty of Engineering and Information Technology, are the driving forces behind Porous Lane, the research-based startup dedicated to creating healthier waterways, cooler cities and a sustainable circular economy.

The two geotechnical engineering experts were driven by a mission to seriously reduce the number of tyres that end up in landfills, stockpiles and illegal dumps. Confident with their new product idea, they joined forces in 2016 to test development of permeable pavements made of recycled tyres in their University of Melbourne laboratory.

During the following four years, they conducted successful field trials in partnership with local councils in Melbourne and Adelaide, and with support from the University of Melbourne, Tyre Stewardship Australia and Sustainability Victoria. The trials tested an optimum blend of paving that provided enough flexibility to reduce cracks caused by movement of natural ground or tree roots – but didn’t become unstable under traffic loads.

“Using all the qualities that make the humble tyre great – sturdiness, elasticity and reliability – we created a surface that squeezes tyre particles tight to quickly create rigidity when supporting heavy loads, such as trucks, cars, buses and bikes,” says Associate Professor Disfani. “And that also helps with stormwater management and flood mitigation”.

Going to market

The laboratory and field trials proved that Porous Lane pavements were cheaper, more durable, and easier to maintain than the current offerings, with the added benefit of using at least 50 per cent recycled content – meaning the team had a commercially viable and environmentally-friendly product on their hands. From there, they started to explore commercialisation opportunities via the University’s ecosystem.

“Mentorship by some of the best entrepreneurs in this space was critical to our success, including from the University’s Melbourne Entrepreneurial Centre and Translating Research at Melbourne (TRAM). It provided us with essential training to understand the commercial process, and with significant support from the University’s Business Development Director, Tech Transfer and IP teams that gave us the time and advice to embark on the startup journey with confidence.”

The outcome

Porous Lane’s clients now include local councils throughout South Australia, New South Wales, Queensland, the Australian Capital Territory and Victoria, and their solution is used widely for tree protection zones, footpaths and bicycle paths.

“Importantly, tens of thousands of tyres have been diverted from Victorian landfills and illegal piles, supplying more water for trees and ensuring less pollution in precious city waterways,” says Professor Disfani.