A new way to make concrete completely circular. This should make it possible to fully reuse the concrete in old buildings, in order to construct a new building. That technique would come in handy in Ukraine, which has been shot to pieces. Hubert Rahier, professor of chemistry and materials science at the Vrije Universiteit Brussel, explains his new invention.
Listen to the interview with Hubert Rahier here.
The essence: Concrete recycling has been around for a long time, but not to the extent that it doesn’t lose quality along the way. That’s what’s revolutionary.
- “What is traditionally done is to grind the concrete into small pieces of concrete and then reuse them. But then you don’t get the same quality,” says the professor. “We have therefore developed a technique in which the concrete is ground in a special way and you can actually obtain the sand, the stones contained in it and the cement separately”.
- “You are going to separate those three original fractions and therefore be able to use them again afterwards. In this way you can actually make concrete from the old concrete with a quality that will be the same as the original,” explains Rahier.
Application: Entire cities in Ukraine were destroyed by Russian shelling. Enter Rahier, who was asked for help by the Ukrainian company Sheldor.
- The technology was not developed specifically for Ukraine, Rahier says. “We started that development years ago, when there was not even talk of that war. We have developed it in the meantime, in fact with the intention of using it here as well. There is of course interest from the companies here, but it is of course interesting that companies from Ukraine have also picked up on that,” he says.
- And Rahier has special help: a host family that he welcomes from Ukraine itself. “We have taken in a Ukrainian family and Inga, who lives with us, has taken care of the translation to ensure smooth communication with the Ukrainian company.”
The challenge: In Ukraine there are still many buildings from the Soviet era, which were built with different techniques and even different materials.
- “There are buildings there that are not made with traditional cement, but with a special alkali-activated cement. That is a material on which I have done a lot of research myself, so we are certainly interested in the different types of cement that are used there. Hopefully we will soon be able to receive genetic material from there to do the first tests.”