Concrete is one of the world’s most used building materials, and researchers are now showing how everyday coffee waste could help make it less harmful to the climate.
Researchers at Australia’s RMIT University have developed a process to convert spent coffee grounds into biochar, a carbon-rich material that can partially replace sand in concrete.
By converting waste into useful resources, this research helps Australia achieve its net-zero objectives and transition to a circular economy. Additionally, it increases public participation in resource recovery and reduces dependency on natural sand.
According to the study, over its lifetime, concrete containing coffee biochar emitted less carbon dioxide. Moreover, the concrete used less fossil fuel and had less impact on lakes and rivers.
In a low-oxygen atmosphere, the researchers heated coffee grounds to about 350°C. The waste is converted into a fine, charcoal-like substance during this process. Subsequently, they replace some of the sand in the concrete with biochar.
Outside of the lab, the RMIT team has already tested the concept on a footpath project and a tiny portion of Victoria’s road infrastructure. These experiments demonstrate how waste-based products can transition from research to practical application.
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