RMIT and regional council brew up a world-first in sustainable footpaths using coffee waste
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Aerial view of the finished footpath in Gisborne. Credit: Chris Matthews, Macedon Ranges Shire Council
In a pioneering move to reduce waste and boost the strength of concrete, RMIT University has partnered with the Macedon Ranges Shire Council to trial the world’s first coffee concrete footpaths.
The project will see spent coffee grounds transformed into biochar, a valuable resource for the construction industry, and incorporated into concrete mixes for upcoming infrastructure projects across Victoria.
RMIT is also collaborating with Australian company BildGroup to deliver these circular economy initiatives on a larger scale.
Dr Rajeev Roychand and his team at RMIT have developed a technique to make concrete 30% stronger by adding coffee biochar produced through a low-energy, oxygen-free process at 350 degrees Celsius.
This innovative approach not only enhances the properties of concrete but also helps divert organic waste from landfills, which contributes to 3% of greenhouse gas emissions.
Australia generates 75 million kilograms of ground coffee waste annually, most of which ends up in landfills. However, this waste could potentially replace up to 655 million kilograms of sand in concrete due to its higher density. Globally, the 10 billion kilograms of spent coffee produced each year could substitute 90 billion kilograms of sand in concrete production.
Dr Roychand said the collaboration with Macedon Ranges Shire Council would see both coffee and wood-chip biochar trialed in concrete footpaths in Gisborne.
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“It’s very exciting to see this world-first trial of our coffee and wood-based biochar in these footpaths,” he said. “Sand is getting scarce over time, and this waste can replace up to 15% of the sand in concrete.”
Council’s Director of Assets and Operations, Shane Walden, welcomed the opportunity to work with RMIT on the groundbreaking project.
“We’re taking those experiments and putting them in ground and in the field today, we’re going to have people walking across the concrete that includes these products and RMIT is going to be coming back and doing testing to see how they stand up,” Mr Walden said.
He noted that despite the use of coffee grounds or mulch, residents would not notice any difference in the appearance or smell of the concrete.
The researchers will assess the performance of the concrete in the trial footpaths, with the goal of supporting wider adoption of this sustainable innovation.
Dr Roychand said the team was working to integrate the research into mainstream commercial applications, and exploring the potential of other organic waste materials beyond coffee.
“Every biochar produced from a different organic material comes with varying composition, in addition to the difference in carbon content, particle size and absorbency, that can boost the performance of concrete in a range of ways,” he said.
The RMIT innovation could also lead to cost savings for the construction industry by reducing the amount of cement required in concrete mixes.
The research has been supported by ARUP Australia, Earth Systems, and RMIT University, with findings published in peer-reviewed journals.
As councils and companies look for ways to reduce their environmental footprint and embrace circular economy principles, the coffee concrete project offers an exciting glimpse into the future of sustainable construction materials.