Scientists discover how to strengthen concrete, and the secret is – coffee

(Patria) - People produce about 4.4 billion tons of concrete every year, using about eight billion tons of sand, which has partly led to acute shortages of construction materials in recent years.

At the same time, about 10 billion kilograms of used coffee grounds are produced during the same period – for which a team of researchers from RMIT University in Australia has discovered can be used as a substitute for silica in the concrete production process.

Moreover, coffee grounds in the right proportions create a much stronger chemical bond than sand.

- Disposal of organic waste poses an environmental challenge because it emits large amounts of greenhouse gases, including methane and carbon dioxide - says the lead author of the study, Dr. Rajeev Roychand from the RMIT School of Engineering.

Roychand emphasizes that Australia alone produces 75 million kilograms of used coffee grounds every year, most of which ends up in landfills, reports Engadget.

Admittedly, coffee grounds cannot simply be mixed with standard concrete because they will not bond with other materials due to their organic content, Roychand explained.

To make it more compatible, the team experimented with pyrolyzing the material at 350 and 500 degrees Celsius, and then replaced sand with it in 5, 10, 15, and 20 percent (by volume) of standard concrete mixtures, reports tportal.

The team found that 350 degrees is the perfect temperature that produces 'a 29.3 percent increase in the compressive strength of composite concrete mixed with coffee biochar,' according to the study published in the new issue of the Journal of Cleaner Production.

- In addition to reducing emissions and creating stronger concrete, we are reducing the impact of continuous extraction of natural resources like sand - added Roychand.