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Subject Area

Civil and Environmental Engineering

Article Type

Original Study

Abstract

Cracks in concrete often occur because of environmental factors like moisture, chemical attacks, and temperature changes. This study investigates utilizing microbial induced calcite precipitation (MICP) to address concrete cracking. Bacillus Sphaericus strain is introduced into cement mortar to enhance its physical and mechanical properties, focusing on crack healing. (MICP) microbial induced calcite precipitation reduces water absorption and capillary coefficient by filling cracks with calcium carbonate using bacterial nutrients. After a duration of 90 days, the bacterial samples exhibit a noteworthy decrease in both capillary action and water absorption when contrasted with the control samples. The bacterial mortar demonstrates accelerated progress in both compressive and flexural strength, showcasing a 145% surge in compressive strength after 90 days and a 148% increase in flexural strength after 56 days, in comparison to the control sample. Reloading the bacterial mortar specimens after 7, 28, and 56 days reveals increased compressive strength compared to the original samples. The enhanced self-healing capacity of the bacterial mortar is validated by the higher compressive strength observed by reloading the samples. Notably, SpM2 (bacillus sphaericus with 1.5% calcium lactate) exhibits a remarkable restoration of strength, reaching 103.34% of its original strength after 90 days. Scanning electron microscopy shows improved density and reduced porosity in the bacterial mortar, while differential thermal analysis demonstrates a higher and more stable calcium carbonate mass in the bacterial samples.

Keywords

Bacteria; Bacillus sphaericus; Microbially induced calcium carbonate precipitation; Scanning Electron Microscopy

Creative Commons License

Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.

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