Coffee grounds increase the strength of concrete by 30%

A research team at the Royal Melbourne Institute of Technology in Australia has announced that it has developed a technology to improve the strength of concrete by 30% by using used coffee grounds. The research team hopes that this technology can solve not only the strength problem of concrete, but also the problem of processing organic waste that causes climate change.

Transforming spent coffee grounds into a valuable resource for the enhancement of concrete strength - ScienceDirect

https://doi.org/10.1016/j.jclepro.2023.138205

Coffee offers performance boost for concrete - RMIT University
https://www.rmit.edu.au/news/all-news/2023/aug/coffee-concrete

Coffee offers performance boost for concrete | RMIT University - YouTube


According to the Royal Melbourne Institute of Technology, 75 million kg of leftover waste left over after making coffee is discharged each year in Australia alone, most of which is disposed of in landfills. In addition, it seems that 10 billion kg of coffee grounds are discharged as garbage every year when looking at the whole world. The disposal of such organic waste is also an environmental problem because it emits large amounts of greenhouse gases such as methane and carbon dioxide that cause climate change.

Rajeev Roichand, a postdoctoral researcher at the Royal Melbourne Institute of Technology, has carbonized coffee grounds in an oxygen-free environment at a high temperature of 350°C to produce biochar.

The bottom left of the photo below is coffee grounds, and the bottom right is biochar. According to the research team, about 22,500 tons of biochar will be generated from 75,000 tons of coffee grounds.

And when 15% of the sand mixed in concrete was replaced with biochar derived from coffee grounds, it was reported that the strength improved by 29.3%.

Professor Gee Lee, the leader of the research team, said that biochar derived from coffee grounds can replace the sand used to manufacture concrete. “The demand for concrete in the construction industry is growing rapidly, with 50 billion tonnes of natural sand being extracted each year around the world,” said Professor Lee. It has a big negative impact, ”he argued that reusing coffee grounds will help solve environmental problems.