Coffee brick homes and what else Australia’s circular economy is delivering
New research offers a circular economy solution for 156,000 kilograms of coffee ground waste every month produced by Melbourne cafes. Photo by Chitokan from Pexels

It might sound like an adult version of Hansel and Gretel, but houses made out of coffee grinds could become a reality in the future.

Researchers from RMIT University in Melbourne have found a way to use coffee grinds in building materials.

The research group, led by senior lecturer in the School of Engineering Dr Srikanth Venkatesan, found that coffee grinds can replace 10 per cent of the sand in concrete mix.

Many concrete mixes are made up of 80 per cent sand, which is the third most used resource on the planet and supplies are struggling to keep up with demand. Extracting sand suitable for concrete can also damage fragile ecosystems. 

The team has also developed and tested a “coffee brick”.

The research offers a circular economy solution for 156,000 kilograms of coffee ground waste every month produced by Melbourne cafes.

“The biggest challenge is ensuring the addition of spent coffee grinds does not lead to a reduction in strength of concrete, and this is the focus of further testing and development to make this product viable for use in real-world applications,” Dr Venkatesan said.

Dr Venkatesan had help on this project from Bachelor of Engineering (Civil and Infrastructure) (Honours) students Senura Kohombange and Anthony Abiad. 

In other circular economy news, research undertaken by the Australian Council of Recycling by independent consultancy MRA highlights the potential of using waste in asphalt and road base.

It found that using recovered soft plastics, secondary glass cullet, and passenger tyre crumb in asphalt and/or road base in the nation’s 12 biggest current road projects, such as Sydney’s Westconnex and the Bruce Highway Upgrade in Queensland, Australia could at least double the amount of soft plastic that is currently domestically recycled, increase tyre recycling by 50 per cent, and help eradicate stockpiles of unused glass cullet in the country.

“The report looked at a current total of about 1000 kilometres of new road, and the results were very positive, ACOR chief executive officer Pete Shmigel said.

“In reality, some 10,000 kilometres of new roads are being constructed; so regular use of recycled material in roads according to a new standard would be a road-led recycling revolution for regional jobs and environmental benefits like greenhouse gas reduction.”

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  1. Would there be aromatic and mould/moisture reducing properties to these coffee brick houses? Quite chic, eh? Coffee grounds as a sterile mushroom growing substrate may provide for more immediate needs in terms of a higher sustainability index.

    I imagine the microplastics in the bitumen would be quite inert, but intuitively prefer their usage in traffic barricades and the like.