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Scientists strengthen concrete by 30 percent with used coffee grounds
(www.engadget.com)
This is a most excellent place for technology news and articles.
From a materials science perspective, a jump of 30% for a material that's been well known for thousands of years seems unlikely.
Well, not really. They only mentioned compressive strength, so other important qualities and measures could be worse in unacceptable ways.
Or maybe it's great. https://www.concretecentre.com/Specification/Innovative-concrete/Charcoal-Concrete.aspx
Two materials that have both been known for a long time.