Road building and civil engineering are creating demand for specialised products that use recycled rubber. This is giving tyres a second life as they are used in their entirety in the manufacture of new solutions for old challenges.
Tyre Stewardship Australia (TSA) explained that more than 56 million tyres used nationwide every year can be recycled for new projects. They can be used to create road surfaces, equine tracks, sound and impact barriers, permeable paving, soil retention and stabilising solutions.
TSA, which was formed to promote the development of viable markets for end-of-life tyres, works with governments and organisations to keep tyres rolling well after they have left the bottom of a vehicle.
In South Australia, the City of Mitcham council worked with TSA on testing the use of crumbed rubber modified asphalt designed to deliver better roads. The municipality has laid a 335 metre stretch of innovative road surface that is undergoing testing to gauge various performance factors, such as cracking, rutting, moisture retention and longevity.
TSA hopes that these tests will result in the increased use of crumbed rubber modified materials nation-wide.
Sustainable horse tracks
A recent trial of a horse track surface, made with a mix of recycled tyre rubber, at Racing Victoria’s Pakenham Racecourse has yielded successful outcomes. The product called Equine Air, by Flexiroc Australia, is a free-draining, low-impact surface that improves water drainage and increases cushioning, thus increasing track utility and reducing injury to horses.
The aim is for Equine Air to become the benchmark for the training surfaces of Racing Victoria, with each track potentially using up to 1,000 tonnes of recycled rubber. There are also plans to look at exporting the concept to racing tracks worldwide.
Pavements that water trees
TSA is also supporting research by the University of Melbourne into the use of tyre-derived products to create an urban permeable pavement that can help provide water to nearby trees. The resulting product improves the flexibility of pavements and allows rainwater to soak through the top surface, improving soil moisture, and reducing surface runoff.
TSA CEO Lina Goodman said in developing and manufacturing new products, and in testing their use for broader application, industry, local government and Tyre Stewardship are addressing a sustainability challenge.
The projects deliver better infrastructure and create valuable jobs in domestic recycling of end-of-life tyres, said Goodman.
“TSA also calls on Australian manufacturing at large to embark in this outstanding opportunity. If any company is searching for a way to differentiate its business, it should consider the features and benefits of tyre-derived products as well as the funding support available through TSA.
“Our support of all activity in this area will increase in the future as we push for ways to create solutions for a previously intractable issue,” she said.
Tyres create durable walls
Other applications include tyres used to create walls. In Western Australia, TSA accredited recycler, Lomwest Enterprises, has created a high-performance wall system using baled end-of-life tyres sandwiched between highly stable concrete skins. This modular walling system is called C4M and can be used for retaining walls, sound barriers, sea walls, and even as blast and impact barriers.
Each C4M module contains 100 tightly baled tyres, can be up to 2.4 metres in height and meets stability, durability and load standards that include the requirements for cyclone shelters and fire-rated partition walls.
New South Wales engineering firm, Ecoflex International, employs recycled truck tyres as the central component of retaining walls that deliver greater stability than traditional construction and offer an extended life to the used tyres.
Constructed in an overlapping crib-like pattern, the gravity walls consist of truck tyres that have had the sidewalls removed that are then filled with crushed rock. The resulting wall offers all the properties of more onerous retaining walls while providing excellent drainage and improved stability in critical soils.
Ecoflex wall systems have been installed at domestic and commercial construction sites. Additional uses include road and railway bases built on wet or unstable terrain.