Scientists have developed concrete materials that can repair their own cracks within 24 hours

According to foreign media reports, concrete has a significant carbon footprint, so improving its performance and making it more durable may have far-reaching environmental benefits. Therefore, this has led to the development of self repairing concrete, which is reported to be able to repair its own cracks. Now, scientists have demonstrated an exciting new form of this material that utilizes an enzyme in human blood.

The small cracks formed in concrete may not immediately pose a problem to the integrity of the building structure, but as water seeps in and cracks spread, they can damage the strength of the building. The concept of self-healing concrete is to intervene in this process when the cracks are still very small. It can seal the material, which not only prevents catastrophic collapse but also expensive maintenance or complete structural replacement.

Over the years, various potential solutions have emerged in this research field. We have seen versions of our own packaging of water glass healing agents, one featuring bacteria producing special adhesives to bond these cracks, and the other using fungi to fill the cracks. Despite the promising prospects, scientists at Worcester Institute of Technology have come up with a solution they believe is cheaper or even more effective.

The team sought inspiration from the human body, more specifically, because an enzyme called carbonic anhydrase (CA) in red blood cells can quickly transfer carbon dioxide from the cells to the bloodstream.

Research author Nima Rahbar said, "We are looking for factors in nature that trigger the rapid transfer of carbon dioxide, which is the CA enzyme." "Due to the astonishing reaction rate of enzymes in our bodies, they can serve as an effective mechanism for repairing and strengthening concrete structures."

To this end, the team added CA enzyme to the concrete powder and then mixed and cast it. When a small crack forms in concrete, this enzyme can interact with carbon dioxide in the air to produce calcium carbonate crystals, which mimic the characteristics of concrete and quickly fill the crack.

Through testing, scientists have demonstrated that their doped concrete can repair millimeter sized cracks within 24 hours. The team stated that this is a significant improvement on the previous technique of using bacteria for self-healing, which is clearly more expensive and even takes up to a month to heal smaller cracks.

Although in the long run, the amount of carbon dioxide absorbed by concrete may be negligible, the true environmental potential of this material lies in its potential lifespan. Rahbar predicts that this self-healing technology can extend the lifespan of structures from 20 years to 80 years, reducing the need to produce alternative concrete, which is a well-known carbon intensive process.

Rahbar said, "Repairing traditional concrete is also very beneficial, as it will help reduce the need for production and transportation of additional concrete, which has a huge impact on the environment."

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