Researchers at RMIT University have developed an innovative way to transform spent coffee grounds into a high-performance construction material, strengthening concrete while tackling the mounting problem of organic waste.
At the heart of this breakthrough is coffee biochar – a carbon-rich material derived from used coffee grounds through a low-energy, oxygen-free heating process. This biochar can replace a portion of the sand traditionally used in concrete, enhancing its strength by up to 30 per cent while simultaneously reducing waste sent to landfill. Given that Australia alone produces around 75,000 tonnes of coffee waste annually, the potential environmental impact is staggering.
Rethinking Waste in Construction
The construction industry faces a dual crisis: an overreliance on finite natural resources and an urgent need to cut carbon emissions. Sand, a fundamental ingredient in concrete, is rapidly becoming a scarce commodity, with global demand projected to rise by 45 per cent over the next four decades. Meanwhile, organic waste in landfills contributes significantly to greenhouse gas emissions.
The RMIT team – led by Dr Rajeev Roychand, Professor Jie Li, and Associate Professor Shannon Kilmartin-Lynch – saw an opportunity to address both challenges in one bold move. By integrating spent coffee grounds into concrete production, their research offers a scalable solution that merges circular economy principles with advanced material engineering.
“What began as research into coffee grounds has now evolved into a comprehensive program converting various types of organic waste into biochar that could help reshape the environmental footprint of the built environment,” Roychand says.
From Lab to the Real World
Unlike many academic breakthroughs that remain confined to research papers, coffee concrete has already made the leap from the lab to real-world applications. Within a year, the RMIT team partnered with industry and government bodies to roll out trials, including a world-first footpath made with coffee biochar in Gisborne, Victoria. The material is also being used in Victoria’s Big Build projects, reinforcing its viability in large-scale infrastructure.
“This Australian-led innovation demonstrates how we can pioneer solutions for global environmental challenges,” says Professor Jie Li.
A Global Vision for Low-Carbon Materials
Beyond Australia, the research is drawing interest from international partners keen to develop high-durability, low-carbon materials. Collaborations with Swedish company C-Green and Australian firm Ambiolock aim to push the boundaries of biochar’s potential, expanding its use beyond coffee waste to a wider range of organic by-products.
“By integrating the circular economy with advanced materials engineering, we’re creating new pathways for reducing carbon emissions while enhancing structural performance,” says Associate Professor Shannon Kilmartin-Lynch.
At a time when industries worldwide are seeking ways to reduce their carbon footprints, innovations like coffee biochar concrete offer a compelling glimpse into the future. “We’re not only addressing waste management but also helping preserve this increasingly scarce natural resource that is vital for construction worldwide,” Kilmartin-Lynch says.
By reimagining waste as a resource, the RMIT team is proving that the path to sustainability might just start at the bottom of a coffee cup.
