Major Road Projects Victoria (MRPV) and project contractor BildGroup have used concrete mixed with biochar made from spent coffee grounds, as a replacement of a portion of the river sand that is normally used, in the Pakenham Roads Upgrade.
Australia generates 75 million kilograms of ground coffee waste every year – most of which goes to landfills.
However, these coffee grounds it could replace up to 655 million kilograms of sand in concrete because it is a denser material. Globally, 10 billion kilograms of spent coffee is generated annually, which could replace up to 90 billion kilograms of sand in concrete.
For this project, Earth Systems converted 5 tonnes of spent coffee grounds – about 140,000 coffees worth of grounds – into two tonnes of useable biochar, which has been laid into the 30 metres cubed footpath along McGregor Road in Pakenham.
The research team at RMIT University developed a technique to make concrete 30 per cent stronger by turning waste coffee grounds into biochar, using a low-energy process without oxygen at 350 degrees Celsius.
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Due to current supply chain limitations, the team could not use their low-energy process to produce biochar so the coffee concrete used in the Gisborne trial had a similar strength to standard concrete.
MRPV program director Brendan Pauwels said coffee concrete had the potential to cut costs and remove vast amounts of waste material from landfill.
“These numbers are remarkable in terms of ecological benefit, and we’re excited to see the Pakenham Roads Upgrade be the first Victorian Big Build project to use the coffee concrete,” he said.
RMIT postdoctoral research fellow Rajeev Roychand, the lead inventor of the coffee concrete, was excited to partner with BildGroup and MRPV for the translation of the RMIT team’s research into Victorian government’s Big Build projects.
“This proactive support plays a significant role in creating a potential for diverting all forms of biodegradable organic waste, which is currently ending up in landfills and contributing to 3 per cent of Australia’s greenhouse gas emissions,” Roychand said.
BildGroup CEO Stephen Hill said he was happy for the company to lead the way and be the first to bring coffee concrete to a major infrastructure project for the Australian construction industry.
“With the coffee concrete we’ve poured, we’re diverting an estimated 140,000 coffees from landfill and saving over 3 tonnes of sand, which have enormous environmental benefits,” he said.
“From a triple bottom line perspective, this just makes good business sense.”
To translate the team’s innovation into a commercial reality, RMIT is engaging with a commercialisation partner and also with companies in the construction and agriculture sectors that would potentially benefit from using biochar products.
