A global company is adding polymers to concrete to create things with the material that has never been possible before.

Credit: theconstructor.org

Concrete has been at the forefront of the construction industry for more than 100 years, but recent developments allow the industry to do more with it than ever before.

Clever chemistry is making concrete more advanced than ever. “We can build higher, we can build slimmer, we can build further underground, and we can build for longer,” says Ian Ellis from BASF, one of the world’s largest chemical companies, in New Scientist magazine.

Ellis is part of a global team at BASF that has developed an array of polymers and associated admixtures capable of changing concrete’s properties – increasing its strength, altering its workable lifetime, improving its rheology and even allowing it to be sprayed onto newly excavated earth.

It was that latter ability that allowed Crossrail to quickly and efficiently develop a 42-kilometre network of new rail tunnels under London. Every time the boring machines excavated a metre or so of the tunnel, robots sprayed a 400mm layer of concrete onto the newly exposed clay. As the concrete emerged from the spray nozzle, it mixed with a BASF accelerator that starts the setting process meaning the millisecond the concrete is in the air, it started to set.

Building upwards creates new challenges for concrete. Much of the concrete poured for the Burj Khalifa had to be pumped up to 600 metres above ground, meaning that by the time it reached height it was already more than one hour old. With the construction taking place in a desert, and the building directly exposed to the blazing hot sun, it was only due to the use of polymers that this build was achieved.

All this is possible using polymers that help the particles of cement bind together when it is meant to set or keep them apart when it is not. Even the process of getting concrete to the construction site is being transformed by chemical intervention. If a truck gets snarled up in traffic, the concrete might begin to set too early, but polymers in the admixture can prevent this.

With availability and the costs of making concrete becoming more of a challenge every year it is likely innovations at companies like BASF that will keep humanity building.