Freshly brewed coffee concrete may soon become a staple in Victoria’s infrastructure, thanks to a groundbreaking collaboration between RMIT University and Macedon Ranges Shire Council.
This innovative partnership has initiated the world’s first trial of footpaths made from concrete incorporating spent coffee grounds.
The initiative is part of a broader effort to transform organic waste into valuable resources for the construction industry.
In addition to coffee grounds, other upcoming infrastructure projects across Victoria will utilise various forms of organic waste, converting them into biochar to strengthen concrete.
RMIT’s team, led by Dr Rajeev Roychand, is partnering with BildGroup, an Australian-owned civil infrastructure, asphalt paving, and road profiling company, to deliver these circular-economy projects.
Their efforts aim to mitigate the environmental impact of organic waste, which contributes 3 per cent of greenhouse gas emissions when sent to landfills.
Organic waste cannot be added directly to concrete because it would decompose over time and weaken the building material.
To overcome this challenge, the team has developed a technique to make concrete 30 per cent stronger by using coffee biochar made with a low-energy process without oxygen at 350 degrees Celsius, to give the drink-additive a “double shot” at life and reduce waste going to landfill.
Australia generates 75 million kilograms of ground coffee waste annually, most of which ends up in landfills.
This waste could replace up to 655 million kilograms of sand in concrete due to its denser composition.
Globally, 10 billion kilograms of spent coffee grounds are produced each year, which could replace up to 90 billion kilograms of sand in concrete.
Dr Roychand noted that biochar from coffee grounds and wood chips could replace a portion of the river sand used in concrete.
“It’s very exciting to see this world-first trial of our coffee and wood-based biochar in collaboration with Macedon Ranges Shire Council,” he said.
“Sand is getting scarce over time, and this waste can replace up to 15 per cent of the sand in concrete.”
Shane Walden, Council’s Director of Assets and Operations, expressed enthusiasm for the project.
“We’re taking those experiments and putting them in the 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,” he stated.
Walden emphasised the importance of such collaborations.
“This not only helps improve the knowledge level of our contractors and our staff, but it also has lots of other benefits and benefits that are important to our community.
“This includes helping the environment, acting sustainably and, most importantly, reducing waste to landfill and having a circular economy,” said Walden.
The researchers will evaluate the performance of the concrete in Gisborne’s trial footpaths, aiming to support the further roll-out of this innovation.
Dr Roychand outlined future goals: “We are currently working in the supply chain sector so that we can make this research into a mainstream product for commercial applications, and we’re not only looking into coffee — we’re expanding this into all forms of different organic waste.”
Potential cost savings for construction companies could arise from reduced cement usage.
Roychand explained that the research indicates that the increased strength of coffee concrete could reduce the required cement content by as much as 10 per cent.
While the current trial did not reduce cement content, future experiments will explore this possibility.
The collaboration between RMIT University and Macedon Ranges Shire Council represents a significant stride towards sustainable construction practices, demonstrating how innovative use of organic waste can contribute to a circular economy and a greener future.
