Researchers from Swinburne University of Technology in Melbourne have found a second-life for the vast amount of coffee grinds thrown away by Australian cafes every day.
Professor Arul Arulrajah, working with PhD candidate Teck-Ang Kua, discovered after a roasting process, the grinds can be mixed with slag (a waste product from steel manufacturing) and an alkaline solution to create cylindrical blocks. The blocks are strong enough to be used as a subgrade material under road surfaces.
The cylindrical blocks were made using coffee grinds from cafes near Swinburne University of Technology’s Hawthorn campus. On average, each café disposes of 150kg’s of coffee grinds weekly.
Professor Arulrajah said as an avid coffee drinker he could see baristas throwing away coffee grounds and so decided to test it as an engineering material.
“We estimate that the coffee grounds from Melbourne’s cafés could be used to build five kilometres of road per year,” said Professor Arulrajah.
“This would reduce landfill and the demand for virgin quarry materials,” he stated.
According to the researchers, the global coffee industry produces millions of tonnes of used grounds each year, most of which end up in landfill.
The research has been published in Volume 115 of Construction and Building Materials Journal.
