Influence of nutrient components of media on structural properties of concrete during biocementation

- Nutrients retarded setting property of cement paste and decreased compressive strength of concrete.
- No impact on setting property of cement paste when admixed with bacterial culture.
- Compressive strength increased and permeability reduced with bacterial treated concrete.
- No significant variation in pH from bacterial treated and control specimens.
- Biogenic precipitation of CaCO3 by bacteria counteract the retarding effect of organic nutrients.

Application of microbial induced carbonate precipitation in cement-based materials has become substantially popular. In the present investigation, effect of nutrient components of media such as carbon and nitrogen content of organic nutrients and bacterial cells on the chemical and structural properties of concrete were studied. The retarding effect of organic nutrient medium on setting property of cement paste and decrease in compressive strength of concrete was observed. However, no impact on setting property of cement paste admixed with bacterial culture was observed. Significant increase in compressive strength and reduction in permeability was observed with bacterial admixed and surface treated concrete specimens. Carbon and nitrogen content were significantly increased in bacterial treated specimens compared to control. No significant variation in pH was observed from the samples collected from different depths of the concrete specimens both in bacterial treated and control specimens. Present study results suggested that biogenic precipitations of CaCO3 by bacterial cells counteract the retarding effect of organic nutrients of concrete and enhance the durability properties.