Pursuing the possibilities of tyre-derived manufactures

A road constructed using tyre-derived rubber products.

Tyre Stewardship Australia discusses its efforts to promote and support the development of new products made from the nation’s burgeoning supply of used tyres.

The equivalent of 56 million tyres are replaced every year in Australia, the majority of which are currently disposed of in landfill, exported for re-use, turned into fuel, illegally dumped, or lying idle in stockpiles. With an expanding population requiring ever more road vehicles, this national waste problem is set to grow. By 2024, over 63.3 million tyres will need to be disposed of. Today, only 10 per cent of end-of- life tyres are recycled locally.

But what if more used tyres could be transformed from waste into useful products, not only reducing harmful environmental impacts, but also potentially creating new industries and employment opportunities?

This is the aim of the Tyre Product Stewardship Scheme, a government- supported, ACCC- authorised industry framework formed in 2014 and administered by Tyre Stewardship Australia (TSA).

“From the perspective of TSA, the reason we want to talk to the manufacturers is because we want to work collaboratively with industry partners to increase the uptake of Australian tyre-derived product,” said Liam O’Keefe, TSA’s market development manager. “Tyre-derived product is a secondary resource that is high volume, that can be utilised as a raw material into new products.”

Since 2015, TSA’s Tyre Stewardship Research Fund – raised via a levy on voluntary participant tyre companies – has committed over $3 million towards research and development (R&D) projects exploring applications for tyre-derived product (TDP) across different industries.

O’Keefe said that, initially, from its inception, the Fund was focused on early stage research activities and had invested in research and development projects. “That means through R&D, we were creating potential markets. This meant we weren’t creating the immediate demand and positive impact on existing commercial entities to the extent that we would have liked,” he said.

As part of the ACCC’s reauthorisation of the Scheme, the structure of TSA’s funds program has been granted greater flexibility, allowing a broader scope to support projects that can demonstrate commercially viable uses of tyre- derived product.

“Now we’ve changed the parameters of the fund to be less R&D oriented and to be more direct,” O’Keefe said. “We want to talk to industry, we want to talk
to manufacturers, and we want to fund demonstration projects and infrastructure projects that can definitively and directly increase the consumption of Australia’s tyre- derived product to create a direct benefit to the resource recovery and recycling markets.”

The roads market, to date, has shown the greatest potential for the up-take of TDPs. Moreover, TSA considers this a vital development, considering the expanding production and disposal of tyres.

“As a nation, we use so many tyres, we drive on the roads, and we’re building more and more roads for more and more cars, so there’s an imperative there that TSA wants to address in conjunction with the roads sector,” O’Keefe said.

“Rubberised roads perform better than standard asphalt roads. So not only is it beneficial from an environmental perspective, it’s beneficial from an engineering perspective too.”

In this area, TSA has co-funded projects alongside Sustainability Victoria, VicRoads, Main Roads WA, The Department of Environment and Heritage Protection and Queensland Transport and Main Roads, the Australian Roads Research Board and the Australian Asphalt and Pavement Association exploring ways to remove barriers to the further uptake of tyre-derived rubber as a modifier in bitumen binders.

O’Keefe explained that the production of these kind of mixes may require separate handling equipment to process the rubberised content, as otherwise residual rubber can impact on conventional mixes being produced on the same equipment. “For the manufacturer of that type of product, we would look to enable them to get specific equipment for the handling and utilization of that rubberised binder.”

TSA is currently working with Polymeric Powders, a small Geelong- based company, which is taking tyre-derived rubber and treating it chemically and mechanically to increase its surface area, before mixing it with polyolefin plastics to manufacture composite materials which have the beneficial properties of rubber and plastic – flexibility and durability. In the long- term, the company is looking towards carrying out large-scale manufacturing of flexible pipes, but O’Keefe said the processes employed can extrude the composite material into most conventional plastic product applications.

Another area where TSA sees potential uptake of tyre-derived product is in the rail industry. The research undertaken to date has involved the University of Wollongong, exploring sub- ballast vibration attenuation applications, one of which is a proprietary product from a company called Ecoflex. The company is producing a rubber-based energy absorbing layer (REAL) that can serve as capping stratum beneath the ballast to minimise railway track degradation. Whole tyres with a sidewall cut off are filled with an aggregate before being installed as a layer underneath the ballast.

O’Keefe said the research indicated that this method can absorb vibration to enhance rail ballast performance and longevity. “It means less of a ballast sub-base is required, and the rubber acts to reduce the vibrations,” he explained. “And it saves money, because you don’t have to dig as deep for the sub- ballast and, because of the reduced vibration, there’s less maintenance, and trains can travel faster.”

Additional projects in the rail sector include projects look at the use of rubber mats manufactured using tyre rubber that can improve rail ballast performance and replace costlier, imported geo-synthetic materials.

The 56 million tyres that expire every year form a vast resource that could be used for productive outcomes. While, previously, the emphasis of the TSA was on promoting recycling and collection, it is now focusing heavily on market development. There is, O’Keefe said, an oversupply of collected used-tyres that now needs to be matched with a steady demand in the form of product development.

“At the moment, that’s the missing link,” O’Keefe said. “In manufacturing and consuming that material, it means that the processors have a market, they’re more viable and sustainable. It’s probably one of the biggest inhibitors to a coherent, strong and fully functioning waste market – across all waste streams.”

From TSA’s perspective, research is an output to deliver an outcome, with that outcome being the increased consumption of tyre-derived product. That means initiatives must demonstrate commercial viability.

“What we’re looking for is articulation through a research programme of a potential benefit, and then correlating that potential benefit to a commercial entity that would be looking to capitalise on that through investment,” O’Keefe said.

“If there are manufacturers looking to utilise that resource, what
we at TSA would say is that we’d be willing to fund research and development and demonstration projects, and we’re also willing to fund infrastructure if you can establish that you can increase the consumption of Australian tyre-derived product through those various stages.”