Bacterial concrete is a self-healing concrete that automatically repairs cracks and makes the structural member structurally sound again. In bacterial concrete, dormant bacteria, along with lime and calcium-based nutrient (generally calcium lactate), are added into the concrete. When there’s a crack greater in width than the micropores already present, it takes in water. The water germinates the bacteria, which then starts feeding on the calcium lactate, making lime. Lime reacts with water to give calcium hydroxide. Calcium hydroxide slowly reacts with atmospheric carbon dioxide to give calcium carbonate (limestone). This limestone permanently repairs the crack.
Bacterial concrete has also shown a higher compressive strength and reduced permeability after action.
Although it isn’t yet a traditional practice to the use bacterial concrete in some specific applications, it can be useful in :
- Freeze-thaw conditios
- When permeability is desired to be reduced
- Enhancement of compressive strength
- Long life buildings
- Seismic zone construction