A team of researchers in Australia have found a way to make concrete stronger and more environmentally friendly.
By adding leftover coffee grounds!
According to their research, concrete made with added coffee grounds is up to 30 percent stronger. (And maybe tastier? Don't test that out!)
This proposal could help to solve two problems at once. The need for more and stronger concrete, and the need to find a better way to dispose of coffee grounds.
So much construction
There is a huge amount of construction taking place around the world. And from buildings to bridges, concrete is a major material. Construction companies use about 30 billion tonnes of it a year!
But making new concrete requires resources, particularly sand. Sand mining, where people extract sand from the ground, can have a huge impact on the environment. Often, this sand comes from riverbanks and beaches—removing too much can change shorelines and habitats.
Finding materials to reduce the amount of sand needed for concrete is a great idea.
So much coffee
Humans also drink a lot of coffee. Coffee is made by passing hot water through ground-up coffee beans. After this process is finished, we have leftovers called coffee grounds.
Worldwide, about 10 billion kilograms of grounds are made every year. Though grounds are compostable, most of it still goes to the landfill.
If coffee grounds can be used as a building material, that means that less of it is going straight to the dump. Perfect!
Heat it up
Making this coffee-concrete is not as simple as just adding grounds straight to the mix though. If you did this, chemicals in the grounds would actually weaken the concrete.
To remove these chemicals, the scientists heated the coffee grounds slowly to over 350°C (660° F) while also removing oxygen from the oven. The final result is a carbon-rich material that is known as biochar. This material bonds exceptionally well with the concrete. And there you have it: super-strong concrete!
The researchers are very excited about their breakthrough, but they did say that the concrete needs to be tested further to know how well it will age. That is important when you're using it to make buildings! But so far, the coffee-crete has passed all their tests for hot and freezing temperatures and stress with flying colours.