Burning rubber: How we’re turning old tyres into new roads
Forget garden swans, here’s a useful way to recycle discarded tyres.
Every hour more than 6000 tyres are dumped in Australia – that’s more than 50 million tyres discarded in landfill or illegal scrapheaps each year. But what if instead of thinking about putting rubber to the road, we put rubber in the road – recycling old tyres to create a new road surface.
It’s already been done in small-scale projects such as children’s playgrounds, but what if we could make streets, or even major roads, using recycled tyres?
It’s a question occupying the mind of Melbourne University academic Dr Mahdi Disfani. The geotechnical engineering lecturer started experimenting with recycling tyres into road surfaces a few years ago and has now set up a real-life testing ground in a carpark.
More than 50 million tyres are discarded to landfill or illegal scrapheaps each year.
The ‘smart’ carpark in Adelaide, an Australian first, incorporates embedded fibre optics to monitor traffic loads and is designed to weather flooding. “With all the solid road, pavement and driveway surfaces in cities like Melbourne, when there’s a heavy downpour there’s nowhere for all the water to go,” says Mahdi. The result? Flash flooding on the roads causing dangerous driving conditions.
He is also testing whether the permeable road surface can act as a filter, resulting in cleaner water seeping underground.
Mahdi has been experimenting with different road surface ‘recipes’ using flexible tyre particles, rigid rock aggregates and flexible glue, in search of the sweet spot, where a surface is flexible and permeable but also stable when driven on.
Permeable surfaces made from old tyres have previously been used as garden pavers but were found to be too flexible to carry heavy loads.