Vol 4; Issue 2: Self-Healing Concrete

Vol 4; Issue 2: Self-Healing Concrete

Concrete is one of the most popular building materials, but it often needs to be repaired because it cracks easily when under tension.  Sometimes it can be very difficult and expense to make these repairs.  Large cracks let water in, which can lead to corrosion of the steel reinforcement, which can be very expensive to replace.  A way to eliminate costs is to use a concrete that repairs itself.  Researchers at Delft Technical University in the Netherlands have created a solution to this problem by creating a bio-concrete.

This concrete is embedded with limestone-producing bacteria which gives it self-healing abilities.  This specific bacteria must able to survive the harsh environment of concrete,  so bacillus bacteria was chosen because it produces spores that can survive decades without food or oxygen. This bacteria and calcium-based feed was added to the concrete mix.  The bacteria repairs any cracks by consuming the feed, carbon dioxide, and oxygen which together produce limestone that fills in the cracks.  The bacteria is activated by water, so it will only produce limestone when the concrete cracks and water gets in.

Using this concrete could lead to significant savings in maintenance.  It would be most useful when constructing structures underground as these are extremely difficult to repair.  By using the bio-concrete, there would be no need for repairs since it will repair itself.  The concrete is still being tested and improved and is predicted to be in the market within the next 4 years.

Cori Treat

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