Can Microbial Concrete Materials Replace Conventional Repair Technologies?

Concrete structures inevitably develop cracks due to mechanical loading, shrinkage, temperature variations, and environmental exposure. Traditionally, these cracks are repaired using methods such as epoxy injection, surface coatings, grouting, and patch repairs. While effective, these techniques often require continuous inspection, labor-intensive maintenance, and significant financial investment throughout a structure's service life. As a result, researchers have explored innovative alternatives, among which microbial concrete has emerged as one of the most promising self-healing technologies.

Microbial concrete incorporates specific bacteria capable of producing calcium carbonate (CaCO₃) when activated by water and nutrients. When cracks form in the concrete, moisture entering the crack triggers bacterial activity. The bacteria metabolize the supplied nutrients and precipitate calcium carbonate, which gradually fills and seals the crack. This autonomous healing mechanism enables the material to repair itself without external intervention, distinguishing microbial concrete from conventional repair technologies.

Despite these benefits, microbial concrete is not yet capable of completely replacing conventional repair technologies. Current bacterial healing mechanisms are generally effective only for small cracks, typically less than 1 mm in width. Larger structural damage still requires traditional repair methods to restore load-bearing capacity and ensure safety. Furthermore, challenges remain regarding bacterial survival in highly alkaline concrete environments, nutrient availability over long service periods, and the scalability of microbial concrete production.