SAMI Bitumen Technologies and State Asphalts NSW are supporting John Holland to trial a new sustainable asphalt on a major project in south-west Sydney. We speak to representatives from all three on how this project could be used as the new standard for sustainable material use.
As providers of different services, one important notion unites John Holland, SAMI Bitumen Technologies, State Asphalts NSW and Sydney Water.
As well as sharing a desire to contribute to the growth of sustainable markets, each organisation has taken action, realising that words aren’t nearly strong enough to turn the tide.
A recent trial incorporating biogenic materials has exemplified this action, while also clearing the way for more organisations across the sector to embrace sustainable alternatives.
Start of something special
More than 12 months ago, John Holland won a tender to deliver the Upper South Creek Advanced Water Recycling Centre and 40 kilometres of associated pipelines for Sydney Water.
This represents a significant project that, when complete, will contribute to future water demand in one of the county’s fastest growing regions.
Kris Bradley – Acting Project Director, Upper South Creek AWRC and Pipelines explains.
“Sydney Water is building the Upper South Creek Advanced Water Recycling Centre (AWRC) in Kemps Creek and associated pipelines to support population and economic growth in Western Sydney. The Sustainable Asphalt trial has been undertaken as part of these works as Sydney Water continues to explore circular economy opportunities for materials, and methods of delivery, in its major infrastructure projects,” Bradley says.
As part of these works, John Holland was tasked with delivering the centre itself, along with a network of under and overground pipelines.
John Holland’s Mark Trethewy, Sustainability Manager, Upper South Creek – Infrastructure Projects, says the first step was establishing strong relationships with material suppliers and designers.
“The Project’s need to establish internal roads surrounding our temporary construction compound and future permanent road works drew John Holland & State Asphalt Services together,” he says. The Project required several internal access roads to construct the wastewater recycling plant. We saw an opportunity for a sustainable alternative and went out to market.”
One such partner was SAMI Bitumen Technologies, one of Australia’s largest providers of bitumen in Australia.
SAMI Bitumen Technologies General Manager Sebastien Chatard says the company’s efforts in the sustainability space is developing a number of environmentally friendly alternatives, such as its SAMIGreen products.
“Last year, we successfully introduced the SAMIGreen range to the market after extensive research and development of the product. Drawing from the valuable experience of our parent company in Europe, we created a high-quality range. Our efforts were recognised when we won the AfPA (Australian Flexible Pavement Association) innovation award in one of the states,” Chatard says.
“We then proceeded to present the SAMIGreen range to the market, and it received positive feedback from the sustainability managers at John Holland. We engaged in multiple meetings and presentations to further discuss the product’s potential.”
SAMI Bitumen Technologies reached an agreement to use its SAMIGreen A15E as a polymer modified binder for SMA mixture as part of John Holland’s works, allowing SAMI to demonstrate the effectiveness and benefits of SAMIGreen in real-world applications.
SAMI’s products, existing relationships, as well as its sustainability vision, all contributed to the company being selected as a key material supplier throughout the duration of the trial.
“Sustainability lies at the heart of SAMI Bitumen Technologies, and our R&D department is dedicated to developing solutions and products that offer sustainable advantages,” Chatard says.
Trethewy states that the trial was an opportunity for the Project team to innovate by using alternative sustainable materials, with the big picture aim of supporting market transformation.
“As organisations like Sydney Water and John Holland look for ways to move towards net zero, consistent engagement with our supply chain will be key. To achieve net zero, industry needs to work together to innovate and find sustainable solutions,” he says.
“Once commissioned, the Upper South Creek Advanced Water Recycling Centre will operate for more than 50 years. In trialling this new material, the project team had to demonstrate that it would stand the test of time. The results show that the material’s performance is equal to a conventional binder, which makes it a viable product for the permanent roads of the facility.”
“It was paramount that we find a material that could reduce our carbon footprint, find a solution for problem waste streams through market application of sustainable materials, and then provide equal or better performance to natural materials and business as usual asphalt products available to the market.”
Related stories:
- SAMI: Technical excellence worldwide
- SAMI: Quality, wherever you go
- SAMI: Future proofing communities
Trial and error
The key objective of the trial was to identify a solution that offers a reduced carbon footprint and solution for problem waste stream in construction materials while maintaining or even improving the technical properties of the material in the field.
In this trial, a 35-millimetre layer of SMA10 mixture, made with SAMI Bitumen Technologies’ bio-based polymer modified binder SAMIGreen A15E, was applied on the base course. State Asphalts, the subcontractor for the project, produced and laid the asphalt. In addition to SAMIGreen, the SMA asphalt produced by State Asphalts incorporated recycled cellulose fibres called PAK-PAVE. PAK-PAVE fibres were developed by State Asphalts using post-consumer coffee cups.
In addition to the trial mixture, a 45-millimetre layer of conventional AC14 with C450 binder was laid as a reference.
“We wanted to optimise and develop the mix, making it thinner, to really get aggressive on that carbon reduction, so there was back and forth between my team and John’s to create a best for Project product,” Trethewy says. “John and the rest of the State Asphalts NSW team were fantastic to collaborate with, along with SAMI. It was great working with both and the partnership formed through the work has been particularly strong.”
“Working with both SAMI and SAS helped to streamline the process. They had the right technical specialists on the ground, reviewing site conditions and providing clear guidance to the Project team, ensuring that we could get the best possible result.”
The trial allowed for a reduction of one centimetre in thickness and a lower carbon footprint due to the use of the plastic fibre incorporation in the SMA mix and polymer modified bio-based binder.
John Kypreos, State Asphalts NSW Director, says the project highlighted the desire across the market for further development of a sustainable materials supply chain. A desire that he says must be satisfied if Australia is to improve its trajectory towards national net-zero targets.
“We have good natural resources and a strong energy market, but the problem is that our industry is carbon intensive,” Kypreos says. “That’s where SAMIGreen fits in, using a biogenic material to lower the carbon footprint of the binder.
“We’ve got a great relationship with SAMI, so we were able to do a lot of research and development in-house. We did our trials and they did theirs, then we’d come back together to share the results. In many ways we’re lucky, we have a recycling yard that’s a nominated area where we’re able to test a lot of these materials. That’s off the back of our work with the Australian Flexible Pavement Association.”
“This trial has provided us with an opportunity to accelerate progress towards these future targets and bring them into the present. It serves as a reminder that with determination and innovation, we can make significant strides towards a sustainable future,” Chatard says.
“The future for projects using sustainable materials looks promising. As the importance of environmental sustainability continues to grow, there is increasing demand for sustainable solutions in various industries, including construction and infrastructure.”
Trial outcomes
The laboratory performance of the asphalt was of a high quality, demonstrating excellent resistance to fatigue and rutting. The carbon footprint of the binder was more than 50 per cent less than the carbon footprint of its corresponding grade and with the required technical properties.
Trethewy says John Holland has been pleased with the success of the trial and the potential for scalability.
“The State Asphalt team, along with SAMI, worked seamlessly together, providing clear and open lines of communication at all times during the trial development and implementation. From a Project perspective our focus lied with delivering a robust and well documented trial replicating real work implementation as much as possible to create genuine results of performance that would showcase if the product would be fit for purpose for the industry in a permanent and long-term application,” he says.
So much so, that Trethewy says this trial will act as proof of concept for future and permanent works applications on the Project and other John Holland Project’s.
“Over the past decade, I’ve witnessed a remarkable shift in the perception and demand for sustainable materials in the construction industry. This shift has created numerous opportunities for contractors, such as John Holland, to explore and implement innovative sustainable materials as they progress towards their net zero goals.” Trethewy says.
Kypreos also sees this project as a turning point for the sector, explaining that there’s no reason why sustainable materials shouldn’t be prioritised for use in infrastructure projects of all sizes.
“I’m extremely proud of the team,” he says. “At the end of the day, we showed that different techniques are applicable, especially when using waste and a low carbon material. I think we’re going to see a lot more of this kind of research coming out and those outcomes coming to large infrastructure builds.
“It’s just a matter of continually pushing the boundaries of what we think is possible.”
This article was originally published in the August edition of our magazine. To read the magazine, click here.