Do you take sugar with your coffee concrete?

An innovation developed at RMIT University has been used for the first time in a major infrastructure project, with coffee concrete being laid into a footpath along a busy road in Pakenham as part of Victoria’s Big Build.

Major Road Projects Victoria (MRPV) and project contractor BildGroup used concrete mixed with biochar made from spent coffee grounds as a replacement of a portion of the river sand that is normally used.

Organic waste going to landfill, including spent coffee grounds, contributes three percent of greenhouse gas emissions.

The waste cannot be added directly to concrete because it would decompose over time and weaken the building material but converted into biochar it can be added to the concrete mix.

Australia generates 75 million kilograms of ground coffee waste every year – but it could replace up to 655 million kilograms of sand in concrete because it is a denser material.

For this project, Earth Systems converted five 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.

RMIT Postdoctoral Research Fellow Dr Rajeev Roychand, the lead inventor of the coffee concrete, partnered with BildGroup and MRPV for the translation of the RMIT team’s research into Victorian government’s Big Build projects.

Dr Roychand said: “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 Australia’s greenhouse gas emissions.”

BildGroup CEO Stephen Hill said: “With the coffee concrete we’ve poured, we’re diverting an estimated 140,000 coffees from landfill and saving over three tonnes of sand, which have enormous environmental benefits.

“From a triple bottom line perspective, this just makes good business sense.”

Picture: RMIT University