Coffee creating concrete carbon clues
Australian university researchers are advancing new ways to cut the carbon footprint of infrastructure by turning spent coffee grounds into useful construction materials.
“We showed that coffee biochar can cut concrete’s carbon footprint in the scenarios we assessed, while earlier trials demonstrated strength gains using the same approach.”
A life-cycle analysis by RMIT University has shown, for the first time, that biochar made from spent coffee grounds can help produce a lower‑carbon concrete while supporting strength benefits seen in earlier lab trials.
Earlier experiments by the RMIT team heated used coffee grounds at about 350 degrees Celsius without oxygen to make a fine biochar. When this replaced 15 percent of sand in concrete, 28‑day strength increased by about 30 per cent, pointing to a practical way to reduce pressure on natural sand supplies.
Building upon the findings, a new study presents a comprehensive life cycle assessment on carbon emissions, resource use, and other environmental impacts from production through to end of life.
The university says the research supports Australia’s shift to a circular economy and net‑zero goals by turning abundant waste into functional materials, reducing reliance on natural sand and building public engagement with resource recovery.
Researcher Dr Jingxuan Zhang says the findings strengthened the case for real‑world trials.
“We showed that coffee biochar can cut concrete’s carbon footprint in the scenarios we assessed, while earlier trials demonstrated strength gains using the same approach.”
Professor Chun-Qing Li, who provided guidance to the research team, says the innovation turned organic waste into a practical ingredient for lower‑carbon infrastructure.
“Using moderate amounts of coffee biochar offers a clear, measurable pathway to lower‑impact concrete,” he says.
The next steps for the study include larger pilots, mix optimisation, and alignment with standards so projects can adopt the findings confidently.
