Hannoversche Kaffeemanufaktur / PexelsUsed coffee grounds, usually thrown in the trash, could strengthen concreteHannoversche Kaffeemanufaktur / Pexels
Once used, coffee grounds become waste, thrown in the trash or used as compost. Now, researchers at the Royal Melbourne Institute of Technology (RMIT), Australia, have found a possible use for them, to replace some of the sand used to make concrete. Because organic compounds in untreated coffee grounds could weaken the concrete, the waste is first subjected to pyrolysis (controlled burning without oxygen) at 350 degrees Celsius, producing a porous, carbon-rich coal. Concrete made with this additive proved 30% stronger than conventional formulations, but tests are still needed to evaluate the durability and performance of the new mixture against abrasion, water absorption, and alternating cycles of freezing and thawing. If validated, this hybrid material could help solve two problems at once: how to dispose of coffee waste and the shortage of natural sand, typically taken from riverbeds and banks around the world (Journal of Cleaner Production, September 20).
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