Stronger concrete made from coffee coming soon?

If you like your morning coffee strong, look out! Researchers have found that strong concrete comes from coffee. Australian researchers say “waste” coffee grounds can make concrete that’s 30% stronger than the normal cement mix.

Stronger coffee for stronger concrete?

Researchers at RMIT University in Melbourne, Australia, replaced 15% of concrete-mix sand with dead coffee grounds. The result was a concrete mix nearly a third stronger than the normal stuff. Stronger concrete’s a good thing—and putting those old dead beans into concrete solves another problem, too. Instead of contributing to the landfill waste stream, old coffee grounds will get a second life.

It’s not as simple as cruising by Starbucks, collecting those leftovers, and then throwing them in a concrete mixer. Untreated, coffee grounds mixed with concrete make the stuff weaker, because the grounds decay. First, the old grounds must be properly treated—or, should we say, heated. Coffee grounds are converted to “biochar” by heating them in an oxygen-free environment at 662 degrees Fahrenheit.

Sidewalk testing coffee concrete

To prove that coffee concrete really is better, the RMIT researchers poured a public concrete sidewalk. Two experimental forms of concrete were poured: one coffee concrete, the other with woodchips instead of coffee grounds. A control walkway using standard concrete mix marked the last part of the walkway. All three types of concrete were laid end-to-end, and time will tell the outcome.

The scientists are so positive from what they’ve found so far that they’re already working on how to get coffee concrete into the supply chain. “We are currently working in the supply chain sector so that we can make this product into a mainstream product for commercial applications, and we’re not only looking into coffee—we’re expanding this into all forms of different organic waste,” said Rajeev Roychand, from RMIT’s School of Engineering. “Every biochar produced from a different organic material comes with varying composition, in addition to the difference in carbon content, particle size, and absorbency, that can boost the performance of concrete in a range of ways.”

If it all works out, concrete retailers’ question for customers will probably be, “Cream and sugar with that?”

##RVT1159b