Concrete is being made 30% stronger with biochar from recycled coffee grounds, thanks to an RMIT University waste and recycling research team whose work has won the Problem-Solver category at Universities Australia’s Shaping Australia Awards.
There’s more to this result – using coffee biochar reduces the amount of sand in the mix as well as landfill and greenhouse gas emissions.
The environmental upside is huge: Australia generates around 75,000 tonnes of ground coffee waste annually, which adds almost seven million tonnes of organic waste to landfill, which creates 3% of the nation’s greenhouse gas emissions.
Meanwhile, sand is becoming increasingly scarce and demand for it is expected to rise by 45% in 40 years. The award-winning team believes second-hand coffee grounds can replace up to 15% of the sand in concrete so biochar is now a valuable resource for the construction industry.
The team – Dr Rajeev Roychand, Professor Jie Li, Associate Professor Shannon Kilmartin-Lynch, Dr Mohammad Saberian, Professor Chun Qing Li and Professor Guomin (Kevin) Zhang – won the award by popular vote and the breakthrough won international coverage and acclaim. ‘Coffee concrete’ has even been profiled on social media by the World Economic Forum.
Team leader Dr Roychand, from RMIT’s School of Engineering, said the award was recognition of the team’s vision to transform waste materials into valuable construction resources.
“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.”
Within a year, the team progressed from the lab to urban applications with industry and government partners, including a world-first footpath trial with Macedon Ranges Shire Council in Victoria.
Other upcoming infrastructure projects around Victoria will also use spent coffee grounds as biochar through the RMIT team’s partnership with infrastructure, road and paving company BildGroup to deliver sustainable projects.
Coffee-concrete is also being displayed in Germany’s prestigious Futurium museum as a new material for a sustainable future. The details can be found in ‘Transforming spent coffee grounds into a valuable resource for the enhancement of concrete strength’, in the Journal of Cleaner Production.
RMIT also collaborates with Ambiolock in Australia and C-Green in Sweden, to advance high-durability, low-carbon, biochar-based materials for sustainable construction worldwide.
Not surprisingly, RMIT is working with a commercialisation partner to turn the innovation into commercial reality. The team is grateful for the support from partners BildGroup, Major Road Projects Victoria, Macedon Ranges Shire Council, Arup, Earth Systems, Reground and Talwali Coffee Roasters.
Header image: Coffee biochar (left) alongside spent coffee grounds in the team’s lab at RMIT. Credit: Carelle Mulawa-Richards, RMIT
