Production and characterization of Bio Caulk by Bacillus pasteurii and its remediation properties with carbon nano tubes on concrete fractures and fissures

Calcite a bacterial bio-sealant is used to seal cracks and holes in buildings and monuments. We have attempted to enhance the production and application of bio-sealant from Bacillus sphaericus with concrete cubes using mix design for the target compressive strength of 50 MPa by response surface methodology. The optimized media was further optimized for pH and nickel concentrations. The column designed for calcite production was packed with mixture of fine Norris sand, fly ash, urea, CaCl2; and the immobilized bacterial species B. sphaericus. After 7 days of a production cycle, the flyash mixture containing CaCO3 was applied to artificially induced cracked cubes. The cubes were investigated for the variation in their compressive strength at 50 MPa and concluded that compressive strength of calcite applied cubes showed increase in strength compared with cement mortar application. The strength was further enhanced to 37.5% by adding 20% of carbon nano tubes to the total sealant.

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► Using central composite design we have optimized parameters for higher calcium carbonate production.
► Our results showed that using Bio Caulk the compressive strength of the cracked cement cubes can be increased.
► We have used bacterial cells to improve strength and durability of fly ash amended concrete.
► The use of fly ash – a recovered resource reduces depletion of natural resources.