31 July 2024
How self-healing concrete could change the built environment
Imagining a world where cracks in our concrete skyscrapers, bridges and pavements mend themselves seems like something from a sci-fi universe. This particular work of fiction is becoming reality however, as new technologies and developments are trialled and tested.
Researchers at the University of East London have developed a recipe to produce self-healing, anti-corrosion concrete.
The project has been funded by Innovate UK and is being carried out with industry partners JP Concrete and Sensicon.
Lead researcher Dr Ali Abbas and his team have been inflicting controlled damage to concrete cubes. The result is narrow cracks that are less than 1mm wide, similar to those that appear in aging or distressed concrete.
The team has been testing how, when exposed to oxygen and water, bacterial spores added to the concrete mixture produce calcite that seal over the cracks.
Finding a way to repair concrete at an early stage prevents any cracks from spreading and reduces the amount of maintenance that the material needs, creating longer-lasting structures.
The next stage of testing has looked at how concrete mixes and the often used steel reinforcement can be enhanced to better withstand corrosion through adding calcium nitrate.
“The good news is that the calcium nitrate admixture (sold as NitCal) does not kill the bacteria – in fact it seems to help it perform better” explained Dr Abbas.
Future-proofing concrete structures and improving the material’s durability helps to save carbon associated with the production of new concrete. To further drive down the embodied carbon, the researchers have been testing how adding supplementary cementitious materials such as GGBS impacts strength and performance.
So far, the results have found that there is no reduction in the concrete’s compressive or tensile strength, showing signs that over time it may even become stronger.
Following the success of this research, the team is looking ahead at how these findings can start to be used in product ranges and make their way into real world building sites.
With futuristic self-healing structures on the horizon, there are ever increasing possibilities to build more sustainably with durable and resilient concrete.
Project team:
Professor David Tann and Dr Ali Abbas – the University of East London
JP Concrete
Sensicon