New Application for Coffee; Recycled Coffee Grounds Make Concrete 29% Stronger

Using spent coffee grounds to replace part of the sand used in concrete strengthens its components while potentially reducing greenhouse gas emissions from coffee grounds in landfills. According to New Scientist, it is estimated that 18 million tons of coffee grounds are produced globally each year, most of which end up in landfills. Their decomposition in landfills releases methane, which is 21 times more potent than carbon dioxide in terms of global warming. Rajiv Roychand from the 'RMIT' University in Melbourne, Australia, and his colleagues thought of finding new applications for coffee grounds in building materials. Researchers found that when the grounds are heated for 2 hours at 350 degrees Celsius in the absence of oxygen, a charcoal-like substance called biochar is produced. Roychand states that adding biochar may strengthen concrete because it has a porous structure that traps moisture. He mentions that this could prevent the concrete from drying out internally and creating fine cracks that can weaken its structure. Replacing 15% of the sand used in concrete with biochar produces concrete blocks that are 29% stronger than regular blocks. Researchers estimate that if all coffee grounds produced annually in Australia were converted to biochar, it would amount to approximately 22,500 tons.