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Coffee as strong as cement? Building the future of construction.

Coffee Beans (Bio-Based World News)

Scientists at Swinburne University of Technology aim to achieve the unfathomable; a coffee mixture as strong as traditional cement that could be used across construction value-chains.

As if that wasn’t impressive enough, the material would also be sustainably sourced from waste produce.

Professor Arul Arulrajah and PhD candidate Teck-Ang Kua is working on this curious study that could redefine how we relate to coffee as an essential product not just for our morning routines but as a larger part of a renewable building material solution.

The soaring world-wide popularity of coffee is creating millions of tonnes per year of waste ground coffee, a waste product that is largely destined for the landfill.

Looking to close the loop on this waste material, scientists saw an opportunity to use the ground coffee to build new value-chains and sustainable processes.

Professor Arul Arulrajah, who leads the geotechnical group in the Centre for Sustainable Infrastructure, has been investigating the use of recycled materials, such as crushed brick or glass and concrete, for use in road construction.

As part of this work, it dawned on him that coffee was a waste material currently under-represented in sustainable markets.

Professor Arul Arulrajah, Axil coffee roasters, Bio-Based World NewsThe idea to use the waste ground coffee sprung from Arul’s own passion for the hot beverage. He explains the inspiration behind his research;

I see the baristas throwing away the used coffee grounds and I think, why not look at this as an engineering material? .

To explore the potential forrecycling this insoluble waste into building materials, Professor Arulrajah alongside PhD candidate Teck-Ang Kua collected waste ground coffee from cafs in the area local to Swinburnes Hawthorn campus.

On average the cafs we collect from dispose of about 150 kg of coffee grounds per week,” says Professor Arulraja, giving you an idea of the availability of the waste resource.

They subsequently dried the material in a 50C oven for five days, then sieved the grounds to filter out any lumps. This was mixed with seven parts of the ground coffee to three parts of slag (another waste product from steel manufacturing). Finally, a liquid alkaline solution was added to bind everything together.

Arul Arulrajah & Teck-Ang Kua in the coffee-testing lab, Bio-Based World NewsThe finished product was astonishing – A mixture that once compressed into cylindrical blocks proved strong enough to use as the sub-grade material in road surfacing, at a level competitive with cement mixtures.

Professor Arulrajah will now push ahead with the success of this solution across wider testing networks;

We estimate that the coffee grounds from Melbournes cafs could be used to build five kilometres of road per year. This would reduce landfill and the demand for virgin quarry materials.”

This miraculous reserach from a team of innovative engineers has proven that waste coffee grounds can be used in building materials for roads, these finding could have limitless potential to improve sustainability across international construction and building material markets.

Bio-Based Live is coming to San Francisco onSeptember 26-27th 2016, for all the latest information and to find out how you can become involved, contact

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