The National Transport Research Organisation (NTRO) and predecessor ARRB have helped to introduce practical, sustainable alternatives to virgin materials for major infrastructure components. NTRO takes us inside this research and outline what’s to come.
In 2020/21, Australia generated an estimated 75.8 million tonnes of waste, equivalent to 2.95 tonnes per person. The biennial 2022 National Waste Report found that Australia’s recycling rate remains stagnant at 60 per cent.
The National Transport Research Organisation (NTRO), previously known as the Australian Road Research Board (ARRB), has had a lasting impact on the development and use of sustainable materials throughout the roads and infrastructure sectors.
NTRO has validated the use of recycled materials like plastic, recycled glass, recycled concrete and brick, reclaimed asphalt pavement, concrete, crumb rubber, recycled solid organics and other recycled roads.
NTRO also works with all levels of government as well as industry, as part of its role to refine and update industry specifications for the use of recycled and sustainable materials.
As NTRO’s Sustainability and Materials Performance National Leader, Dr Clarissa Han oversees and advises the delivery of research and practical work into recycled or alternative materials. She says the NTRO plays an invaluable role in promoting the use of recycled materials.
“We’ve been researching sustainable options since we started. We are a thought leader in Australasia across the innovative material science space,” she says.
“The vision for sustainability and materials performance is to accelerate the transformation of Australia to a circular economy. Our focus has been on increasing the use of recycled and upcycled materials to support the sustainability and resilience of transport infrastructure.”
The resilience aspect also ties back to performance. In part due to NTRO’s research, many recycled materials can now perform as well as, if not better than their virgin material counterparts.
By using current sustainable materials, contractors and asset owners can help to increase the resiliency, durability and chance of road failure across Australia’s road network, while also helping to reduce the volume of material being sent to landfill.
An aspect where NTRO plays an integral part.
“We offer quite a wide spectrum of services, knowledge and solutions. We develop standards and specifications, which we constantly review. These provide solutions for developments such as noise walls made out of recycled plastic, recycled plastic pipes and more,” Han says.
“We also have the national materials laboratory that’s national standard lab and NATA accredited. We do a whole spectrum of testing services for our aggregates, binders, asphalt.
“We offer the commercialisation pathway for emerging industry products to be applicable to the transport infrastructure sector. We also give supporting services like a lifecycle evaluation, environmental impact assessments and legislation analysis.”
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NTRO also undertakes a thorough approvals process to ensure that its specifications are both accurate and appropriate.
“For the development and publication of these specifications there’s quite a rigorous process to help the end user. It always goes through a review of both domestic and international best practice against existing specifications,” she says.
“There’s reflection, consultation and a couple of rounds of reviews.”
Dr Han says the persistence and hard work of NTRO has been a contributing factor in helping to influence the industry’s culture and perspective on recycled materials.
“Even a couple of years ago, there was this kind of conservative culture. But I’m impressed by the way people are learning and accommodating sustainability,” she says.
“More often than not in this sector you’ll find that community and industry move faster than government. Our role is really to connect the forefront of research with an understanding from key stakeholders.
“Their understanding of this knowledge is very important. That’s why we go through this testing, evaluation and trial process to help collect evidence and present it to them. That’s the most satisfying part of this whole process.”
Giving plastic a purpose
One of NTRO’s key projects has been research into the re-use of plastic and its implementation into infrastructure components.
A report last year from NTRO provided insight into the potential for one of Australia’s most problematic waste streams. Per NTRO’s research, plastic can be used across a variety of applications for building both road and rail infrastructure.
Principal Professional Dr James Grenfell’s work as part of the SMP team, as well as collaborative projects with the National Asset Centre of Excellence and the Western Australian Road Research and Innovation Program has helped to further investigate the potential of this material.
He says the first big milestone for the NTRO team was the involvement of state government departments and subsidiaries.
“We were looking at implementing recycled plastics into transport infrastructure in a safe and sustainable way,” he says.
“We have done quite a bit of work with Major Roads Project Victoria (MRPV), helping them to develop fit-for-purpose, performance specifications to be used in certain applications. That way if anyone can design a recycled plastic product that can meet the performance requirements, then there’s a clear pathway to these products being used.”
MRPV’s interactions with NTRO led to the development of a performance-based technical specification for noise walls implementing recycled plastics.
“The use of recycled plastic in transport infrastructure has expanded away from just asphalt and bitumen modification to ancillary devices like noise walls, safety barriers, pipes and more,” Grenfell says.
“You name any product; chances are we’ve looked into it to see what could be done in Australia from either a manufacturing or recycled plastics processing perspective. Then it’s also essential to understand what the potential barriers could be to implementation, such as a lack of specifications or a lack of knowledge.”
Dr Grenfell says the team at NTRO are always looking for ways to change specifications to encourage greater innovation, while accelerating the use of recycled materials.
“Sometimes products don’t fit within a certain specification, even though they meet the performance requirements. A lot of old specifications can be very prescriptive,” he says.
MRPV implemented noise wall structures containing recycled plastic content on the Mordialloc Freeway. These were a proprietary product, where industry had innovated to allow recycled materials to be used, whilst still meeting the desired requirements.
However, the newly implemented noise walls did not meet the current specifications, which were very prescriptive and did not allow recycled plastics to be used. MRPV had the desire to use the product more readily, but needed a specification to allow them to do so. NTRO was then engaged by MRPV to develop a performance-based specification for plastic noise walls that did not prevent recycled plastics from being used.
“DTP’s Chief Engineer wanted us from the outset to develop a specification with a view of it becoming an Australian-wide specification, not just a Victorian specification,” he says.
Shortly after, Grenfell and his team received word that other state departments were interested in the newly formed specification.
“Other road agencies that were working with plastics said that as long as there was a quality output, they would likely adopt [the specification] as well. It was a sign that our expertise was being recognised.”
This specification has now been approved and published on the Austroads website as ATS 4450 and is free to download.
Another example where NTRO is working in the recycled plastics space is assisting with the implementation of recycled plastic and composite rail sleepers in Australia. These are designed to replace regular timber and concrete sleepers. In the case of timber sleeper replacement there is the possibility to extend their lifecycle by three to four times.
NTRO’s journey is just beginning, with a variety of projects and developments already underway. This includes on-going bids and investigations into new specifications and guidelines.
This article was originally published in the September edition of our magazine. To read the magazine, click here.