“Lead author Dr Rajeev Roychand from RMIT University said the team developed a technique to make concrete 30% stronger by turning waste coffee grounds into biochar, using a low-energy process without oxygen at 350 degrees Celsius.”
Australia throws out 75 million kilograms of coffee grounds a year, most of it into landfill. RMIT bakes it into biochar and swaps it in for part of the sand in concrete. Construction burns through 50 billion tonnes of natural sand a year, mostly dug out of river beds. Several councils have already engaged the team for infrastructure projects. Landfill methane becomes road base.