Old tyres: From running on the roads to being part of them

Tyre Stewardship Australia has been helping create a circular economy by finding new ways to use waste tyres, from crumb rubber asphalt to permeable pavements.

In just a few years Tyre Stewardship Australia (TSA) has established a prominent role in assisting the development of new products and increased applications for tyre-derived products. Many of the products are helping to deliver better roads, pavements and urban infrastructure.

“It’s all part of finding more sustainable ways of dealing with our annual challenge of 56 million end-of-life tyres” Liam O’Keefe, TSA Market Development Manager says.

As one of the three main goals for TSA, the drive to build a stronger domestic market for tyre-derived products has seen the organisation commit (to date) $3 million to research and development projects focused on opportunities for growth.

Mr. O’Keefe says the market development work in this area has focused on two key opportunities. The option to increase established uses for recycled tyres, such as in road building, and identifying innovations with a high tyre-derived material use potential that are worthy of further research and support.

ROADS

“Crumb rubber asphalt (CRA) and spray-seal with a crumb rubber content have both been used in Australia since the 1970s. They are proven to deliver superior performance in terms of noise, drainage and durability under harsh climactic conditions.” Mr. O’Keefe explains.

TSA is working with state roads authorities on increasing the volume of rubber crumb used in roads construction and maintenance nationally.

“Results have already started to flow, with VicRoads increasing the mix of rubber crumb specified for spray-seal from five per cent to 10 per cent and committing to increasing the use of crumbed rubber products in new road construction,” Mr. O’Keefe says.

“Plus, Queensland Transport and Main Roads has been conducting field tests of both CRA open graded asphalt and spray-seal.”

PERMABLE PAVEMENTS

Mr. O’Keefe says a more surprising example of innovation in road building and urban infrastructure is a TSA-funded research project – in cooperation with the University of Melbourne – on permeable paving. The paving allows water to flow through to the underlying soil.

“Permeable paving can even work to provide much needed moisture to nearby trees. Other possible benefits include increased groundwater recharge, reduced surface run-off, decreased risk of flash flooding, help with treatment of storm water and preventing pollution of connected water bodies.”

The materials allow rainwater to soak down between the pavements, which are then able to provide water for nearby trees.

Research is looking at the suitability of using up to 60 per cent waste tyre product in pavements that form part of more comprehensive irrigation and storm water management solutions for urban areas.

Working with Tasmanian company Merlin Site Services the university is researching the use of rubber granule mix permeable paving and taking those findings into the field through a pilot installation program. Mr. O’Keefe says the objective of this is to provide the construction/civil works industry and local governments with the confidence to further increase the use of tyre-derived products (TDP).

“TDP can help to deliver enhanced pavement characteristics that are a very valuable ingredient in meeting a complex engineering challenge,” Mr. O’Keefe says.

“The aim of TSA’s investment in this research is to support the use of a very high percentage of TDP in new products that can provide additional beneficial uses for recycled end-of-life tyres.

“To progress this further, we’re looking for partners, particularly in the local government sector, to run trials with the permeable pavement to use it in bike tracks and car parks. I am sure there are innovative councils that are interested in the benefits this can offer.”

Through investment in a wide range of market development projects, TSA is working to realise existing and new opportunities for better solutions, which deliver the dual benefits of a cleaner environment and new ‘green’ jobs,” Mr. O’Keefe says.

It is particularly fitting that the extended lifecycle of tyres running on our roads could see them becoming part of our future roads and pavements.”