Costain pioneers self-healing concrete
Costain is planning to trial prototype self-healing concrete considered to be the Holy Grail of building materials science.
The contractor will part finance the cutting-edge project contributing £600,000 to research to create an inbuilt concrete immune system that reacts to repair wounds and cracks.
The experimental concrete has several lines of defence. Scientists are developing special bacteria contained within protective microcapsules that can be added to the original mix.
These microbes are sparked into life once water enters a crack to produce limestone deposits plugging cracks before water and oxygen can corrode steel reinforcement.
At the same time the concrete will use specially developed polymer tendons, like conventional steel rods, that can be activated to shrink and close gaps.
The three-year, £1.6m Materials for Life research project is being carried out jointly by Cardiff, Cambridge and Bath Universities.
They will work with Costain and other stakeholders, including BRE, Highways Agency, the Welsh Government and Atkins to test and develop the advances.
The products developed will be trialled at several Costain sites from Spring 2015 once the technology is fine-tuned.
“This is cutting-edge technology and Costain’s involvement once again underlines our commitment to innovation,” said Andrea Green, project manager.
“Self-healing concrete could be a game-changer for the industry, with the potential to enhance durability, improve safety and dramatically reduce maintenance costs.”
Oliver Teall, a Costain graduate civil engineer, who will carry out research leading to a PhD at Cardiff University will be looking at how shape memory polymers can be used to help heal cracks in concrete.
“Polymer tendons are incorporated into the concrete. If a crack occurs, these tendons can currently be activated by either heat or an electrical supply. They then spring back to their original shape, compressing the concrete and closing the crack,” he explained.
“Researchers at Bath and Cambridge are looking at calcite producing bacteria and microcapsules that contain healing agents respectively. The aim is to combine all three areas of research to create multi-scale damage immunity and pave the way for a new generation of construction materials.”