Paving our recycled future: ARRB

The road construction industry can contribute to the circular economy by creating sustainable roads for a sustainable society, writes Melissa Lyons, Senior Professional Leader, the Australian Road Research Board.

Sustainability, recycling, circular economy – these are the current buzz words in the road construction industry.

The road construction industry is under pressure to help solve Australia’s recycling crisis. The make-up of roads lends itself well to the incorporation of recycled materials. 

However, this is not as simple as replacing raw road construction materials with recycled materials such as glass, plastic or rubber. The right approach must be taken.

We need to think about how we can incorporate recycled materials into our roads in way that will make the road more sustainable in the long term, rather than a way to help solve the recycled material stockpile issues we have now.

Without the right research, development and planning, we risk creating a new waste stream in years to come if we can’t reclaim the road.

Roads play an important role in our transport system. They keep our economy moving. We need to ensure we are not de-valuing or degrading them. Roads are not ‘just’ asphalt, they are valuable assets that need to meet certain requirements for our society to function.

The road construction industry should be designing and constructing our roads with the confidence that they will meet or exceed current standards. Society still expect our roads to perform well, if not better, especially as technology progresses.

However, these roads also need to be sustainable in order to support a more sustainable society.

Society is heavily influenced by marketing and it is also influencing the way our industry is embracing sustainability. It is important that the road construction industry support the basic principles of the waste hierarchy – reduce, reuse, recycle.

We need to be careful to not give society justification to keep generating recycled waste.

Standard asphalt is 100 per cent reusable as Reclaimed Asphalt Pavement (RAP). The use (and re-use) of RAP reduces the amount of virgin materials used in maintenance, rehabilitation or new construction of asphalt and pavements.

This means valuable materials are used over and over again and do not end up in landfill, directly contributing to a circular economy.

There are many aspects to consider across the pavement lifecycle. There are many innovative products using recycled materials on the market and laboratory tests that show positive performance results.

However, many of these products have not considered the full cradle-to-grave lifecycle of the recycled materials and the road.  Recycled materials in some cases may increase the performance of the road, but it may also change how it is processed and manufactured and how we can reuse it.

Therefore, we need to make sure we think about how our current processes and equipment will need to be updated to be compatible with the new products we are creating.

There may be trade-offs and risks with adding new recycled materials. There are costs and benefits of each material, use and design.

For some recycled materials there may be more valuable and lower risk road infrastructure applications that can use more recycled materials e.g. bike paths or roadside furniture.

Full life-cycle assessments of road technology options can assist in the best technology selection for the right situation.

For the road construction industry to contribute to a circular economy, we need to make a conscious effort to not just offer short term solutions to our recycling crisis.

When we incorporate recycled materials into our roads and road infrastructure, a rigorous research and development process should be undertaken. 

Learnings from international uses, laboratory testing and local demonstration trials with performance monitoring are all part of this.

ARRB are working with state road agencies, local government and bodies such as Sustainability Victoria and Tyre Stewardship Australia, undertaking trials and developing standards and guidelines to ensure the smart implementation of recycled materials.

Interested in finding out more about this work and its potential application, or customisation to your needs? Contact ARRB at sustainability@arrb.com.au

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City of Parramatta trials Reconophalt roads

City of Parramatta Council in NSW is trialling two innovative sustainable road solutions aimed at reducing waste materials and combatting heat.

In the first of these trials, Chelmsford Avenue in Epping and Honor Street in Ermington were resurfaced with Reconophalt.

Manufactured by Downer, the product contains recycled soft plastics from plastic bags and packaging, waste glass and waste toner from used printer cartridges.

According to City of Parramatta Lord Mayor Bob Dwyer, single-use plastics and other waste materials are a growing problem for the region.

“Finding new ways to recycle and reuse materials means we can reduce the amount of waste that ultimately enters landfill,” he said.

“By taking tonnes of plastic and glass from local recycling plants and using it to create roads, we are able to turn trash into treasured infrastructure.”

Downer Pavements General Manager Stuart Billing said the equivalent of approximately 500,000 plastic bags, 165,000 glass bottles and 12,500 toner cartridges are diverted from landfill for every one kilometre of a two-lane Reconophalt road.

“Together with the City of Parramatta, we are creating new avenues to recycle and repurpose waste materials into new streams of use, and reducing the community’s reliance upon increasingly scarce virgin materials,” he said.

The project is partially funded through the NSW Planning, Industry and Environment Department’s ‘Waste Less, Recycle More’ initiative.

The second trial, which is being conducted in partnership with Blacktown and Campbelltown councils and Western Sydney University, will examine how lighter coloured roads can help reduce the amount of heat being absorbed and retained by roads on hot days.

“As Western Sydney can be several degrees hotter than suburbs in the east, it is crucial we explore ways we can keep our streets cooler – especially in the summer,” Mayor Dwyer said.

“Parramatta is going through an incredible period of growth and transformation, and council is dedicated to building a sustainable and innovative city that will meet the needs of our community well into the future. These road projects are just two examples of how we are achieving this.”

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Recycled plastic used to resurface Melbourne streets

The City of Melbourne is using plastic previously destined for landfill to resurface five prominent city streets.

According to Lord Mayor Sally Capp, the first road to be re-surfaced with asphalt made with recycled plastic was Flinders Street, with works occurring between Exhibition Street and Spring Street in October.

“We collect 11,000 tonnes of residential recycling each year. Using a mix of plastic to resurface our streets is one way we can support the circular economy and reduce landfill,” Ms Capp said.

“The paving on these historically significant streets will look exactly the same as any other street. The difference is that using plastic in the asphalt creates demand for recycled products.”

Sections of Anderson Street in South Yarra have also been resurfaced, with further works on Alexandra Avenue to be completed this week.

Ms Capp said works will also be completed on sections of Spring Street next year, between Little Collins Street and Little Bourke Street and Flinders Street and Collins Street.

Deputy Lord Mayor Arron Wood said the paving consists of 50 per cent recycled plastics and other recyclable materials such as slag aggregates and recycled asphalt products, with the remaining made of virgin materials.

Mr Wood said the trial will allow the city to assess whether it can use more recycled materials and plastic for road resurfacing.

“The City of Melbourne uses 10,000 tonnes of asphalt annually, and we resurfaced eight kilometres of road last year. This trial will help us understand whether it’s possible to use recycled plastic in more of our major projects,” Mr Wood said.

“By using recycled plastic and other recycled materials on our roads we’re creating more sustainable infrastructure and showing there are local markets for recycled materials.”

The trial is a joint initiative from the City of Melbourne, its subsidiary Citywide, and the Citywide North Melbourne Asphalt Plant, with plastic waste sourced from metropolitan Melbourne.

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Millions of tyres could soon be used in Australia’s roads

New national specifications for Crumbed Rubber Modified (CRM) asphalt could see millions of waste tyres being used in Australia’s road infrastructure.

The Australian Asphalt Pavement Association (AAPA), Tyre Stewardship Australia (TSA), Main Roads Queensland, Main Roads WA, Sustainability Victoria and the Australian Road Research Board have worked together to develop and analyse research and development data to achieve cohesive national standards.

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The new national specifications could see nearly 10 per cent of the accessible feedstock for Australian tyre-derived crumb rubber used in domestic road manufacturing, which adds up to almost 4 million end-of-life tyres every year.

The document was published by the AAPA national technology and leadership committee to facilitate the construction of demonstration trials of CRM gap graded asphalt (GGA), and to promote the use of CRM open graded asphalt in Australia.

The crumb rubber binder technology is based on the technology used in the US, with the first demonstration section of CRM GGA in the Gold Coast placed in late June.

CRM Asphalt can offer better drainage, reduced noise, improved rut and crack resistance and reduced maintenance cycles.

Engineers and road contractors are now able to work within parameters of the new national specifications to take advantage of CRM asphalt and spray seal.

TSA Market Development Manager Liam O’Keefe said reaching a national standard has been a critical part of increasing the potential market for crumb rubber use in Australian roads.

“To fully realise this potential for that use we must continue to work with industry partners to ensure the delivery of better roads and better environmental outcomes for all,” Mr O’Keefe said.

“The important next phase of the task is ensuring that the new specifications are used. As utilisation of the new specifications grows, so too will the benefits to the end- of-life tyre industry.”

AAPA Director of Technology and Leadership Erik Denneman said this is a great outcome that has come from the close collaboration between industry and road agencies in Australia.

“For AAPA this initiative fits our objective of encouraging the efficient use of available resources and promoting the use of sustainable products,” Mr Denneman said.

The new national specifications can be found here.

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