• 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.
Alice Klein

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

Read these too
Cheap solar cells on the walls of buildings could soon be reality
Dr Xiaojing Hao has been competing with other researchers in the solar cell industry to produce the world's most efficient thin-film cell yet.
Can we turn atmospheric carbon into cement?
A pilot plant based in Newcastle is working on locking carbon dioxide up in rock, making useful building materials in the process.
Solar freakin' roadways? Why the future of this technology may not be so bright
Solar roadways need a complete technological rethink to be effective, writes photovoltaics researcher Andrew Thomson

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