Coffee is often referred to as a strong drink. Now, after its proven success in holding together concrete, the word strong has an entirely different meaning.
BildGroup works in and around communities every single day, aiming to reduce its carbon footprint and minimise its use of raw materials.
A wholly Australian-owned business, BildGroup builds infrastructure and facilities by delivering diverse solutions, like civil infrastructure, urban development, landscaping, sports fields, road profiling and asphalt paving.
Like the rest of the construction industry, BildGroup had constructed concrete paving using sand and cement to produce a sound and structurally safe product.
This all changed when it discovered an innovation RMIT University created, known as ‘coffee concrete’. This sustainable concrete promises a safe and environmentally friendly way to reduce the sand content in concrete.
In partnership with RMIT University and concrete supply partner Dandy Premix, BildGroup has successfully trialled the new concrete, made partially from the coffee grounds that remain after the coffee is brewed.
The spent coffee grounds are turned into biochar, a form of charcoal produced by heating organic waste materials in a low-oxygen environment, known as pyrolysis.
The biochar acts as a partial sand replacement in the concrete. Sand is a finite and precious resource that BildGroup and other construction companies hope to preserve.
The coffee concrete is the latest sustainable innovation BildGroup has taken part in.
In doing so, the company is one of few leading the way in environmentally friendly construction.
Gary Fox, Project Director for Pakenham Roads Upgrade – BildGroup, says discovering the RMIT research was an exciting moment for the team, which also marked the beginning of a new partnership.
“At BildGroup, we encourage new innovations on our projects, and we always keep an eye out for new construction practices and how we can incorporate them into our business,” says Fox.
“When we looked at this research, it ticked a lot of our boxes internally, so we were excited to reach out to RMIT to help bring it out of the lab and into a real-world scenario.
“Innovation is part of our DNA, and after learning more about the coffee concrete, we saw a fantastic synergy to work with RMIT to help them bring their idea into a commercial delivery space.”
Behind the brew
With the original intent to recycle aluminium coffee pods, the RMIT team knuckled down to find a way to keep them out of landfill.
Discussing matters over cups of coffee, Dr Rajeev Roychand and his fellow RMIT researchers, Professor Jie Li, Associate Professor Shannon Kilmartin-Lynch, Dr Mohammad Saberian, Professor Chun Qing Li and Professor Guomin (Kevin) Zhang discovered they should start at the source.
“We intended to find an alternate end source for the huge amount of waste that ends up in landfills,” says Lead Author Roychand.
“Instead, we thought we should look at the coffee itself.”
According to Roychand, Australia generates 75 million kilograms of ground coffee waste every year, most of which goes to landfills.
“We 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,” says Roychand.
This transforms the waste into a stable, carbon-rich material for various applications, including construction.
By utilising coffee biochar, Roychand says the cement content can also be reduced, a welcome reduction considering cement is a carbon-heavy material.
“Cement is the highest carbon footprint emitting material within concrete. It is responsible for seven to eight per cent of global greenhouse gas emissions a year,” he says.
“Cement is what adds the strength component of the concrete, so when we discovered we could make the concrete up to 30 per cent stronger, with the addition of coffee biochar and no increase in cement, it was a momentous moment.
“This process opens up cost savings for construction companies, as it has the potential to reduce the amount of cement needed by as much as 10 per cent.”
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From lab to reality
Soon after Roychand and the team began publishing their results, they started generating a lot of interest from outside parties, with BildGroup being one.
BildGroup began identifying partners to help bring the research onto a live project.
“It wasn’t hard to get our concrete supplier and client, Major Road Projects Victoria (MRPV), on board,” says Fox.
“Like BildGroup, our concrete supply partner, Dandy Premix, believes in leading innovations. All parties were excited to participate in this eco-friendly solution.”
The coffee for the project was supplied by social enterprise Reground, which collects ground coffee from businesses and diverts it back to the local community for use in a host of circular ideas.
Earth Systems, an environmental, social science and engineering company, was responsible for producing the biochar for the project.
Fox says BildGroup is proud to be at the forefront of this circular economy solution with its partners, turning organic waste into valuable resources.
“It is inspiring to see multiple organisations uniting to work towards a common goal to achieve new innovations of sustainability,” he says.
“This project demonstrates the sheer power of organisations working together for positive social impact.”
A new footpath in the Cardinia Shire Council, situated in south-east Melbourne, was the destination chosen for this collaboration.
As part of the Pakenham Roads Upgrade with MRPV, the works are the first project of its kind in Australia and the construction industry.
In this trial, over 30 cubic metres of coffee concrete was poured, diverting approximately five tonnes of spent coffee grounds from landfill, the equivalent of 140,000 lattes.
The five tonnes of spent coffee grounds turned into more than two tonnes of biochar, replacing the traditional sand used in the concrete mix.
This also equates to saving three tonnes of sand.
After eight months of working closely with all parties, Fox says the project was a great success.
“We felt it was a great opportunity to continue our partnership with MRPV. They jumped on board after we conducted a series of tests and trials to ensure it was a commercially viable option and we could complete a concrete pour on a work site,” he says.
To coincide with BildGroup’s recycled first and sustainability commitments, Fox says the trial was a perfect opportunity to try something new while helping RMIT advance its research.
“We are always looking to reduce our carbon footprint and contribute to the circular economy, all while saving on raw materials,” he says.
“If we can utilise the humble cup of coffee in construction, then we will relish the opportunity. It’s something that we’re proud to be a part of.”
In addition to the coffee concrete trials, BildGroup has supported and used recycled asphalt for use on other projects, recycled plastics in drainage pipes, solar lights on site to power sites and electric equipment.
“As a multi-disciplinary contractor, we are a business that wants to fulfill the potential of our people and our community,” says Fox.
“We are excited to lead the charge in some of these innovations and are happy to assist as much research as we can to build a better future.
“Trials have to start somewhere; we are happy to help develop them and be involved.”
This article was originally published in the May edition of our magazine. To read the magazine, click here.
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