Coffee ground waste is a popular substance for researchers working on sustainability. They’ve tested its use for things like biofuels that power machines and even large cities like London to a medium that can help solve global warming and a filter that can pull mercury from water. In Australia, university researchers recently looked at combining spent coffee grounds with steel production and other byproducts to create a greener road pavement.
If it works, they theorize the new road pavement product will reduce landfill wastes and the need for quarried resources. Coffee waste is ubiquitous--it’s the most popular beverage in the world.
I see the baristas throwing away the used coffee grounds and I think, ‘why not look at this as an engineering material?’” said Swinburne University researcher and engineering professor, Arul Arulrajah.
According to New Atlas, Arulrajah and his team dried spent coffee grounds in an oven for five days at 122° F, filtered it and mixed it with steel manufacturing “slag” in a ratio of seven parts to three. They then added liquid alkaline as a binder and compressed the mix into cylindrical blocks.
The blocks proved to be an effective subgrade road construction material in testing. They published their findings, Strength Assessment of Spent Coffee Grounds-Geopolymer Cement Utilizing Slag and Fly Ash Precursors, in the Construction and Building Materials journal.
The Melbourne researchers estimated that the coffee ground waste from just that city’s local cafes could supply more than 3 miles of road pavement per year.
