The global consumption of coffee is anticipated to reach around 175 million bags within the next year, leading to over 23 billion pounds of used coffee grounds.
Historically, this waste has mostly ended up in landfills, contributing to significant greenhouse gas emissions during transport. However, these leftover coffee grounds represent a significant resource waiting to be recycled. Now, scientists at RMIT University in Australia might have found an innovative solution.
As highlighted in a recent article in the Journal of Cleaner Production, engineers have crafted concrete that is approximately 30% more robust than conventional varieties by incorporating coffee-derived biochar.
The team transformed the used coffee grounds into a charcoal-esque substance using a process called pyrolysis, which heats organic waste to 350°C in an oxygen-deprived environment, thereby avoiding carbon dioxide production.
They then replaced about 15% of the sand typically found in concrete with this coffee biochar, resulting in a stronger material that also addresses a significant food waste challenge.
In a conversation with The Guardian on August 22, Kilmartin-Lynch mentioned that although coffee biochar has a finer structure than sand, its porous nature enables superior bonding with cement. Preliminary tests suggest that this coffee-infused concrete has impressive structural potential.
The substitution of traditional concrete’s sand content provides another significant advantage. The university pointed out that every year, construction projects worldwide consume around 50 billion metric tons of natural sand, impacting delicate ecosystems like riverbanks.
By reducing the reliance on sand extraction and instead using recycled coffee grounds, this innovation also brings about a positive environmental change.
With successful further refinements and research, it’s conceivable that all discarded coffee grounds could be redirected towards fresh concrete developments.
The scientists are now keen on establishing practical implementation guidelines and initiating field tests with external industry experts. Collaborations with other innovative teams, such as those working on diaper-based concrete, might also be on the horizon.