The NSW Government has released new guidelines to boost the use of asphalt containing recycled crushed glass on infrastructure projects across the state.
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.
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.”
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.
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.
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.