Coffee grounds make concrete 30% stronger

Australian engineers claim they can make concrete nearly 30% stronger by incorporating processed coffee grounds .

Every year, the world produces about 10 billion kilograms of coffee grounds, most of which end up in landfills. The disposal of this organic waste poses an environmental challenge because it releases large amounts of greenhouse gases such as methane and carbon dioxide, which contribute to climate change.

Meanwhile, with the global construction market booming, the demand for concrete also causes a series of other environmental challenges. The global exploitation of natural sand, from riverbeds to riverbanks to meet the rapidly growing demand of the construction industry, has had a major impact on the environment.

Researchers in Australia used coffee grounds to make concrete stronger. (Photo: Guardian).

"We can keep coffee grounds away from landfills and also better conserve natural resources such as sand with the above approach," said engineer Jie Li, working at RMIT University (Australia). , speak.

Organic products such as coffee grounds cannot be added directly to concrete because they release chemicals that reduce the durability of building materials. Therefore, the team heated the coffee grounds to 350 degrees Celsius while removing oxygen from the grounds.

This pyrolysis process helps break down the organic molecules in coffee grounds, creating a carbon-rich porous charcoal called biochar , which can bond well with cement.

They converted coffee grounds into biochar and then used this material to replace some of the sand needed to make concrete. The process involves heating coffee waste to about 350C to create biochar. The researchers found that replacing 15% of the sand typically used in concrete with coffee biochar enhanced the concrete's durability by 29.3%.

Dr. Shannon Kilmartin-Lynch, co-chair of this study, affirmed that the idea came from the desire to reduce waste products from coffee.

Samples of coffee beans, roasted coffee beans, coffee grounds, and coffee biochar. (Photo: Guardian).

The team of researchers is collaborating with local authorities on future infrastructure projects such as building walkways and sidewalks. They argue that this technique could benefit the environment because it reduces the amount of coffee grounds going to landfill as well as reducing the need for natural sand used in the construction industry.

According to the Australian National Food Waste Strategy Feasibility Study, food waste accounts for about 3% of the country's annual greenhouse gas emissions. Besides, Australia generates about 75,000 tons of coffee waste each year.

Researchers estimate that if all the coffee grounds discarded in Australia each year were converted into biochar, the resulting volume would be around 22,500 tonnes.