• Engineers have turned coffee grounds into building materials for roads (Pixabay)Source: Pixabay
Aussie scientists have come up with a way to turn used coffee grounds and steel manufacturing waste into a building material for roads.
By
Alice Klein

Source:
New Scientist
3 May 2016 - 9:43 AM  UPDATED 3 May 2016 - 11:08 AM

Your morning pick-me-up could make your drive smoother. Engineers have turned coffee grounds into building materials for roads.

The global coffee industry produces millions of tonnes of used grounds annually, with most ending up in landfill. But Arul Arulrajah at Swinburne University of Technology in Melbourne, Australia, believes that this material should not go to waste.

“One of my hobbies is drinking coffee,” he says. “One time when I saw my barista throwing the used grounds in the bin, I thought, why not look at this material from an engineering perspective?”

Arulrajah and his colleagues collected soggy coffee grounds from the bins of a local café and dried them in a 50 °C oven. They mixed seven parts coffee grounds with three parts of a waste product from steel manufacturing called slag and added an alkaline solution to bind everything together.

Then they compressed the final mixture into cylindrical blocks, which were strong enough for use as the layer of road that sits under the surface and provides foundations.

“We estimate that the coffee grounds from Melbourne’s cafés could be used to build 5 kilometres of road per year,” says Arulrajah. “This would reduce landfill and the demand for virgin quarry materials.”

The research reflects a trend towards using green construction materials, says Caroline Baillie of the University of Western Australia. “Even ordinary companies are starting to develop recycled building materials – it’s not just the crazies anymore.”

A key next step will be ensuring that the energy required to create coffee-based building materials is not so high that it outweighs the recycling benefits, says Baillie.

Journal reference: Construction and Building Materials, DOI: 10.1016/j.conbuildmat.2016.04.021

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This article was originally published in New Scientist© All Rights reserved. Distributed by Tribune Content Agency.