SAMI Bitumen Technologies is ushering in a greener future for the transport sector, with recent trials exemplifying the progress of sustainable road construction materials. Experts in the field reflect on the success so far of SAMIGreen Crumbflex.
Carbon and waste reduction are just some of the driving principles behind SAMI Bitumen Technologies’ continued progression in the sustainability space.
Knowing that development alone isn’t enough, the company is making a renewed push for more projects in the field, hoping that examples and case studies will accelerate the sector’s transition to the use of more sustainable materials.
In January this year, SAMI Bitumen Technologies conducted a new project of its innovative SAMIGreen Crumbflex.
Stephen Bernard, Research and Development Supervisor – SAMI Bitumen Technologies has been pivotal in the development and testing of SAMIGreen Crumbflex. He’s driven by a personal desire to see more sustainable outcomes achieved quicker throughout the infrastructure and transport sectors.
“Part of the reason why I’m at this company is that it gives me an opportunity for a wider impact. I know that changes we make in the lab can essentially effect the entire country if we can get a great product out there,” he says.
“For me, it’s about pushing products like this out there to get more trials done, to get that field experience. If the Arctic ice sheets melt and sea levels rise by 20 metres, it’s not going to be theoretical, it’s going to be a state of ‘we need to do this now’. It’s so important that we’re ready ahead of time.”
Transport for NSW gave Colas the opportunity to trial its ECO asphalt with SAMIGreen Crumbflex product as part of works in Tomago, New South Wales.
Bernard says SAMIGreen Crumbflex is a natural evolution of the initial SAMIGreen product, granting improved sustainability outcomes when used in conjunction with conventional materials and techniques.
“SAMIGreen was initially developed with the idea of a 50 per cent carbon reduction,” he says.
“We already have a lot of experience with the Crumbflex product, which was developed in-house several years ago. It’s basically about taking those learnings and combining them with the performance of SAMIGreen. SAMIGreen Crumbflex just extends the product range even further.”
SAMIGreen Crumbflex is an innovative polymer bio binder consisting of biogenic additives, crumb rubber from end-of-life tyres, and elastomeric additives.
It’s estimated that carbon footprint of this product is more than 50 per cent less than conventional A15E (polymer modified binder), while providing the same binder and asphalt properties.
Kanjana Yindee, Group Technical Manager ANZ – SAMI Bitumen Technologies says SAMI Bitumen Technologies has experts in the field, along with best-in-class facilities to conduct such testing.
“We combine our team’s expertise and extensive experience in polymer modification with the use of SBS (styrene-butadiene-styrene), renewable biogenic materials, and recycled components like crumb rubber in the binder formulation,” she says.“We did some tests by comparing the functional properties of the asphalt mix made from the SAMIGreen Crumbflex and regular PMB (polymer modified bitumen) before the trial and we didn’t notice any technical difference between the two materials.”
The main objective of the ATP was to offer innovation products to lower the carbon footprint without having detriment to the performance of the pavement. The team aimed for the highest amount of RAP it could get through the plant, safely managing 33 per cent, previously achieving 25 per cent in other mix types. This provided a result of 41 per cent recycled material in the ECO mix.
Lee Whitehead, Group Major Projects Manager – COLAS Australia says ECO asphalt was one of a number of proposals he put forward in 2023, with funding from Transport for NSW and the Australian Flexible Pavement Association supporting the project.
“The project was part of the Transport for NSW Asset Technology Program, where I had submitted a paper for the innovation of low carbon asphalt, which would not only reduce the carbon footprint compared to current asphalt mixes, but would also be equal or better in performance to the current prescriptive specified mixes allowed in New South Wales,” he says.
“The addition of SAMIGreen Crumbflex is one carbon reducing element to the whole asphalt mix design.”
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Trial results
Having been present and overseeing the Tomago project, Bernard says the performance and outcome has been overwhelmingly positive.
“Everything’s been performing perfectly. As far as I’m concerned, the lab results in the asphalt have been really good and the field performance has been excellent,” he says.
“All of those initial questions that we laid out, we were able to answer and now package up those findings to pass on to relevant road authorities and local government areas.”
Another important aspect, on top of the product’s performance, was the user experience. Bernard and an R&D team were active in acquiring insights from the ground crew on site, to further learn how the product fared compared to other materials.
“We spent a lot of time talking to the crews, taking photos, closely observing to make sure it was a smooth process,” he says.
“It was very straightforward, they made it in the plant no problem, it was fine loading in the truck, compaction, field performance, they did their joints, they were able to transfer everything off, everything went fine.”
Yindee says the SAMIGreen range binder performed similarly to conventional binders in laboratory tests and field trials, with no significant differences in functional properties, showing it can be a direct replacement without compromising performance.
“The paving team also pointed out that the new binder flowed as smoothly as conventional PMB during discharging and laying,” she says. “Overall, the crew was really happy with the product, without the need for any changes to the mix design.
“The SAMIGreen range binder can be used without any procurement issues, allowing it to be easily substituted for conventional binders in sustainable projects. With a product like this, performance and a low carbon footprint go hand in hand.”
She adds that products such as this are far more than a trend, instead representing real and positive change. She predicts a positive future for the product, driven by growing market demand for sustainable solutions, the product’s ability to meet sustainability goals, as well as its competitive pricing.
“By working together, I believe industry stakeholders can make real progress toward a future where the environmental impact of road construction is minimised. Whenever a project needs a sustainable approach, or has sustainability targets, we can propose this binder without any procurement issues to the relevant road authority or contractor,” she says.
“It’s ready to be used straight away.”
This article was originally published in the December edition of our magazine. To read the magazine, click here.
