Coffee grounds spark concrete revolution, boosting strength by 30%
Engineers in Australia have discovered a new application for coffee grounds in the construction industry, increasing their utility. This waste, previously overlooked from the coffee brewing process, can enhance concrete strength by nearly 30%.
This research, published by "The Guardian," appeared in the "Journal of Cleaner Production." Scientists from RMIT University in Melbourne have developed an innovative method of processing coffee residues, which can be used to create more durable concrete.
Adding modified coffee residues to the concrete mix can increase its resistance by 29.3%. Experts also highlight that the pyrolysis process used in this method is energy-efficient.
How to strengthen concrete with coffee grounds?
Dr Shannon Kilmartin-Lynch from RMIT, co-creator of this technology, addresses the problem of wasting coffee grounds and capsules. He emphasises that this solution tackles the inefficient management of these wastes. When processed into biochar—a material akin to charcoal—they can replace some of the sand used in concrete production.
As Dr Rajeev Roychand from RMIT explains, when creating biochar from coffee residues, it is essential to heat them in anaerobic conditions to prevent CO2 emissions.
According to scientists, Pyrolysis, a key element of this method, involves heating the grounds to 662 degrees Fahrenheit, which is relatively energy-efficient. This process typically requires higher temperatures, reaching 1652 degrees, but coffee requires slightly more than 662 degrees.
Benefits of using coffee wastes
Research indicates that incorporating 15% coffee biochar into the concrete mix increases its strength by nearly 30%. Additionally, coffee wastes are porous, facilitating cement bonding with biochar.
Although the RMIT team's research is still in its preliminary stages and further testing on material durability is necessary, scientists are already collaborating with local authorities to utilise reinforced concrete in future infrastructure projects, such as pavement construction.
Another advantage is the reduction in the amount of coffee grounds reaching landfills. If all Australian coffee waste were recycled, up to 22,000 tonnes of eco-friendly concrete would be produced annually.
