Researchers in Australia discovered that by processing and adding burnt coffee grounds to the mix, we could produce concrete that is 30% stronger.
Their novel recipe has the potential to cure numerous problems at once.
Every year, the globe generates an astounding 10 billion kilograms of coffee waste. The majority of it ends up in landfills.
“The disposal of organic waste poses an environmental challenge because it emits large amounts of greenhouse gases, including methane and carbon dioxide, which contribute to climate change,” says RMIT University engineer Rajeev Roychand.
With a thriving worldwide construction sector, there is also an increased need for resource-intensive concrete, posing new environmental challenges.
“The ongoing extraction of natural sand around the world – typically taken from river beds and banks – to meet the rapidly growing demands of the construction industry has a big impact on the environment,” explains RMIT engineer Jie Li.
“Due to the finite nature of resources and the environmental impacts of sand mining, there are critical and long-term challenges in maintaining a sustainable supply of sand.” We could keep organic waste out of landfills and better protect natural resources like sand if we adopted a circular-economy strategy.”
Organic items, such as coffee grounds, cannot be mixed directly into concrete because they contain compounds that degrade the material’s strength. As a result, the researchers used low energy levels to heat coffee trash to over 350°C (about 660° F) while depriving it of oxygen.
This is known as pyrolyzing. It degrades the organic molecules, producing biochar, a porous, carbon-rich charcoal that can form bonds with and thereby insert itself into the cement matrix.
Roychand and colleagues also attempted to pyrolyze the coffee grounds at 500°C, but the resulting biochar particles were weaker.
The researchers emphasize that they have yet to evaluate the long-term durability of their cement product. They’re now investigating how the hybrid coffee-cement holds up to freeze/thaw cycles, water absorption, abrasions, and a variety of other stresses.
Read More: Why does Coffee Irritate the Stomach?
The group is also working on producing biochar from other organic waste sources, such as wood, food waste, and agricultural waste.
“Our research is in its early stages, but these exciting findings offer an innovative way to greatly reduce the amount of organic waste that goes to landfill,” says Shannon Kilmartin-Lynch, an RMIT engineer.
“From an Indigenous perspective, inspiration for my research includes caring for country, ensuring a sustainable life cycle for all materials, and avoiding things going into landfill to minimize environmental impact.”
