State Asphalts NSW has partnered with government and the private sector to develop a method for sustainable road construction.
According to The Junk Map, Australia produces approximately 76 million tonnes of waste annually.
The construction industry is responsible for producing 12.7 million tonnes of waste per year, with construction and demolition now the largest source of waste nationally.
Company’s such as State Asphalt NSW have recognised the need for action to increase the sustainability of construction materials for the roads sector. Especially when it comes to domestic reprocessing.
Australia is heavily dependent on exports for waste processing. In 2018 alone, 4.5 million tonnes of waste were exported overseas, costing $2.8 billion.
At this current pace, Australia will need to increase waste reprocessing by up to 400 per cent to achieve the national recycling target of 80 per cent by the year 2030.
Factors such as the COAG waste ban, a regulation on the exports of waste streams such as glass and plastic, as well as impacts on global trade and exports caused by the COVID-19 pandemic have placed a greater demand on localised reprocessing facilities and organisations.
Between 2015 and 2019, State Asphalts NSW opened a discussion around developing adequate infrastructure to transform mixed plastic and paper waste to modifiers used in asphalt.
The idea
State Asphalts has more than 20 years’ experience in asphalt manufacturing. As such, the company is well versed in the evolving landscape of asphalt production.
James Ng, State Asphalts NSW Project Manager, says the need for asphalt additives – that increase the durability, resistance and performance of asphalt surfaces – has placed a strain on availability.
“At a supply chain level, a lot of our additives and a lot of our specialty materials that go into asphalt are generally imported,” Ng says. “Australia doesn’t have the speciality chemical and materials complex enough to deliver certain additives.”
Ng says State Asphalt NSW has experienced the pros and cons of importing internationally first-hand, an enduring challenge during a period of supply chain disruptions.
“Previously we’ve been caught in a pretty big bind, because some of these materials are quite niche, such as a particular construction material,” he says.
“We’ve needed materials within a week’s time frame, but without having that local supply we’ve had to look to countries in Europe and Asia.”
“That acted as a catalyst for us to ask ourselves ‘is there an opportunity to use a local material’ and if we did, could that maybe be a waste material?”
Coincidentally, the first dialogue around the potential for using local waste streams occurred at a waste industry event prior to COVID-19.
State Asphalts NSW Director John Kypreos ran into a Closed Loop Environmental Solutions (Closed Loop) contact, where a conversation started around the collection of coffee cups.
“Rob Pascoe had a coffee cup in his hand and he said ‘would you find a way to put this back into roads’. I put two and two together. I picked up the phone and rang the next day,” Kypreos says.
“From there we touched base, and the rest is history.”
Closed Loop had begun a proprietary collection of used coffee cups, objects that may seem commonplace, but contain a valuable source of waste polymer-coated paper board. The collection formed part of the company’s ‘Simply Cups’ initiative, as Ng recalls.
“The risk with any proprietary collection is that you often have an abundance of supply before you are able to generate demand,” Ng says. “But there was a collection solution, it was a pretty clean material stream, Closed Loop just needed offtake partners to design products to use the material.”
“We thought ‘hang on a second, what about asphalt’?”
State Asphalt NSW viewed asphalt as a composite material that could host a number of ingredients. Ng looked to the examples of RAP (Reclaimed Asphalt Pavement), RCG (Recycled Crushed Glass), and Crumb Rubber (Recycled End-of-Life Tyres); materials with a strong track record of improving asphalt sustainability.
Kypreos says the opportunity was one that State Asphalts NSW wasn’t going to pass up.
“The ambition for the overall project is to give us a circular economy project that brings us on par with our opposition, while also moving towards a net zero carbon initiative,” he says.
This marked the birth of State Asphalts NSW’s PAK-PAVE Roads Initiative, a concept to engineer road construction products from packaging waste.
The Penrith PAK-PAVE Roads uses PAK-PAVE Fibre, an asphalt fibre additive derived from recycled coffee cups.
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The concept
State Asphalts NSW identified key partners for research and development on the project, which was supported through a CRC-P (Cooperative Research Centres Program) grant from the Federal Government.
The project attracted “significant contributions” from Closed Loop, the University of New South Wales (UNSW), Primaplas and Asphaltech.
State Asphalts NSW, along with the other partners, initially set out to develop sufficient infrastructure and technology to convert both paper and plastic wastes into asphalt additives.
As part of the project, UNSW collaborated to evaluate and test the materials and develop a process through its laboratories and equipment.
State Asphalts NSW and Asphaltech will use the material as part of its production, while Closed Loop and Primaplas will provide a source of materials to manufacture the asphalt additive.
Professor Nasser Khalili, Head of School – Civil and Environmental Engineering UNSW Sydney, says the project aligns with the University’s motivations.
“Sustainability is important for the whole world,” Khalili says. “It’s essential if we’re to preserve this wonderful planet and pass it on to our future generations in a liveable condition.
“[This project] is providing an opportunity to solve one of the major environmental concerns to society and the public at large.”
Professor Khalili, along with Associate Professor Ailar Hajimohammadi and Dr Babak Shahbodagh-Khan are regarded as leading researchers in this field.
Using the university’s geotechnical facility, as well as the participation of PhD students, the UNSW team conducted independent research to analyse, test and commercialise the asphalt additive.
“State Asphalts NSW approached us initially. Normally it works the other way around. I believe that’s an important aspect of this project, that the industry initiated the collaboration,” Khalili says.
“This particular project is very important at the moment as you can do very little with plastics. Exporting plastic used to make this waste somebody else’s problem. Now we have to deal with it, and there’re very few technologies that can convert plastic into a value-add for asphalt.”
Khalili says he’s proud of UNSW’s contributions to the project and to society.
“I’m really excited about how effective the technology can be in absorbing plastic waste and adding value to our asphalt industry,” he says.
The milestones
On the journey to producing PAK-PAVE Roads, State Asphalts NSW had to establish two manufacturing systems, one for the plastic and one for paper.
The paper recycling focused on developing the asphalt fibre additive. Without the fibre, an aggregate mix would have an open structure. This structure can only contain low amounts of bitumen.
The plastic recycling focused on the development of waste polyethylene and polypropylene to aid bitumen modification.
Further evaluations were made during development and testing, such as a fibre distribution analysis, binder testing, development of production systems and the procurement of equipment.
State Asphalt NSW operates four manufacturing facilities. The company placed an emphasis on applying proven equipment and technologies, such as separation, drying and pelletisation, rather than developing equipment from the ground up.
Ng says State Asphalts NSW’s ethos of trial and error helped to forge a path for the successful development of the product for trials in Sydney’s west.
“We’re not afraid of trying something new,” he says. “We’re happy to be innovators. We’re happy to get it wrong and try again until we get it right.”
The final manufacturing process, while intricate, is basic in premise.
Once collected, cup waste is processed and shredded to form an CLESmix. This mix is then converted into the PAK-PAVE fibre. This fibre is then combined with aggregates and bitumen to create PAK-PAVE Roads.
The benefits
The PAK-PAVE Road patent has shown unambiguous benefits when it comes to sustainability and reducing the carbon footprint of road construction.
While containing more than 50 per cent of recycled waste materials such as coffee cups, glass, RAP and steel furnace slag, PAK-PAVE Roads also show improved pavement durability and crack resistance. This also includes increased resistance to skids caused by wet weather and reduced noise levels from the surface texture.
The project will also have wider benefits for the industry.
State Asphalts NSW expect the project to increase Australia’s capacity to recycle waste streams through a value-added product.
Developing the technologies and infrastructure required for production will also create new manufacturing industries, while increasing the competitiveness of the road construction and asphalt manufacturing industries.
The project is also expected to accelerate the process for recycling plastic and polymer coated paper waste.
For Ng, one of the most exciting developments has been the increased collaboration between independent researchers, government and private enterprise.
“One of the most exciting things about the project has been getting to work with subject matter experts at great detail and finding solutions to collective challenges,” he says. “When you’ve got a problem, it’s great to be able to get the smartest people we can find into a single room to discuss it.
“To be able to solve these issues, have a plan and actually deliver it, it’s been a really rewarding experience.”
The outcome
PAK-PAVE Roads has recently undergone trials in Penrith, Sydney. This suburban road is now the first in the nation to contain recycled coffee cups as part of its construction.
The first pilot projects for PAK-PAVE Roads are set to take place in South Penrith and Erskine Park. Further trials will be conducted with LGAs over the coming months, with hopes that the PAK-PAVE Roads development will see a wider rollout in the future.
“The future’s exciting,” NG says. “We’ll continue to bring together the right regulators, technical subject experts, industry and commercial and public stakeholders together. It’s really been quite incredible.
This article was originally published in the May edition of our magazine. To read the magazine, click here.