Researchers turning coffee grinds into concrete

A new project from RMIT University is attempting to use coffee grinds for concrete manufacturing.

According to an RMIT statement, Australia drinks 1.3 million cups of coffee every day, meaning the grinds represent a potentially untapped reuse material.

“As part of the venture, a keen coffee-loving engineering lecturer and his students have looked to the construction industry for a novel solution to reduce the amount of coffee grinds going to landfill – using them in concrete,” the statement reads.

“Most concrete mixes contain up to 80 per cent sand – the third most used resource on the planet. But even this seemingly endless resource cannot keep up with current demand, and extracting it from places with fragile ecosystems can have a huge environmental impact.”

The team has found they can replace up to 10 per cent of sand in a concrete mix with coffee grounds and have produced sample ‘coffee bricks,’ which will be on display at RMIT’s EnGenius event Wednesday 23 October.

“With concrete mixes containing up to 80 per cent sand, the group found coffee grinds could replace up to 10 percent of sand in concrete mixes,” the statement reads.

Bachelor of Engineering students Senura Kohombange and Anthony Abiad worked with senior School of Engineering researcher Srikanth Venkatesan to test and develop the ‘coffee bricks.’

Dr Venkatesan said as a regular cappuccino drinker he was inspired to find a solution to the waste he was making each day.

“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.

Swinburne University did similar tests in 2016 to determine if coffee grounds could be used in subgrades.

Lab testing indicated the mixture was strong enough to compare to other road binder materials however it had yet to be tested in practical applications to determine performance over time.

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