Australian researchers have discovered that processing burnt coffee grounds and adding them to a mix could potentially produce concrete that is 30% stronger.
Their clever recipes can solve multiple problems at once.
Every year, a staggering 10 billion kilograms of coffee waste is generated around the world. Most end up in landfills.
“The processing of organic waste poses environmental problems because it emits large amounts of greenhouse gases such as methane and carbon dioxide, which contribute to climate change,” explains Rajeev Loichand, an engineer at RMIT University.
As the construction market booms around the world, demand for resource-intensive concrete is increasing, and new environmental issues are also being raised.
RMIT engineer Jie Li said: “Natural sand extraction continues around the world to meet the rapidly increasing demands of the construction industry, typically from riverbeds and embankments, but this is not environmentally friendly. It’s having a big impact.”
“Due to the finite nature of resources and the environmental impact of sand mining, maintaining a sustainable sand supply poses significant long-term challenges. Circular economy approaches keep organic waste out of landfills and We can preserve it better.”Our natural resources are like sand. ”
Organic products such as coffee grounds cannot be added directly to concrete because they will leach chemicals that weaken the strength of the building material. So the team used low energy levels to heat the coffee waste to over 350°C (about 660°F) while depriving it of oxygen.
This process is called pyrolysis. It breaks down organic molecules and produces porous, carbon-rich charcoal called biochar, which can be incorporated into the cement matrix by forming bonds with it.
Roychand and colleagues also tried pyrolyzing coffee grounds at 500 °C, but the resulting biochar particles were not as strong.
The researchers warned that the long-term durability of cement products needs to be evaluated. They are currently working on testing how the hybrid coffee cement performs under freeze/thaw cycles, water absorption, abrasion, and many other stressors.
The team is also working on creating biochar from other organic waste sources such as wood, food waste, and agricultural waste.
“Although our research is at an early stage, these exciting findings provide an innovative way to significantly reduce the amount of organic waste sent to landfill,” said RMIT engineer Shannon Kilmartin.・Mr. Lynch stated.
“The inspiration for my research from an Indigenous perspective is to care for our country, to ensure a sustainable lifecycle for all materials, and to avoid landfilling to minimize our impact on the environment. To avoid being exposed.”
Their research is Cleaner production journal.
A previous version of this article was published in September 2023.