A world-first trial is underway in Central Victoria in the form of a coffee concrete footpath, which has been developed by RMIT University alongside the Macedon Ranges Shire Council.

Regarded as a catalyst for other coffee concrete projects, the footpath comprises biochar formed from coffee grounds, which could serve as a vital resource in the built environment for years to come, pending the success of the trial. Asphalt paving company BildGroup will work with the university to deliver each project, including the one in the Macedon Ranges.

Coffee is made some 30 percent stronger via coffee biochar made with a low-energy process without oxygen at 350 degrees. It serves as coffee’s potential second life – with some 75 million kilograms of ground coffee produced by Australians each year. The increased density of coffee grounds in comparison to sand could see the discarded material replace up to 90 billion kilograms of sand in concrete worldwide.

“Despite the fact that we're using coffee grounds or mulch, residents aren't going to really see or smell any difference in this concrete product,” says Macedon Ranges Council’s Director of Assets and Operations Shane Walden.

“It's really important for Council to be involved in projects such as this and to be working closely hand in hand with universities such as RMIT. 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.”

RMIT Researcher Rajeev Roychand says he and his colleagues hope the sustainable concrete solution becomes commonplace throughout the construction industry.

“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,” he says.

“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.”

RMIT says it plans to use less cement in future trials, as the Macedon footpath did not reduce the amount of cement used for similar projects in this instance. To read about the findings, click here.