Vacuum impregnation of bacillus pseudofirmus into fine lightweight aggregate

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Conference Proceeding

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Bacterial concrete is one of the most promising self-healing alternatives due to its ability to seal crack widths through microbial induced calcite precipitation (MICP). In this process, alkali-resistant Bacillus pseudofirmus bacteria are embedded in concrete to precipitate calcium carbonate to seal the cracks. Due to concrete's harsh environment, it is critical to protect the bacteria to ensure the viability of this technology. One of the key protection techniques is vacuum impregnation into porous aggregates. The objective of this study was to evaluate the impregnation efficiency of Bacillus pseudofirmus into fine lightweight aggregate by using three different nutrients, namely, magnesium acetate, calcium lactate, and sodium lactate by using a vacuum impregnation chamber. To achieve this objective, a vacuum impregnation chamber was used to impregnate Bacillus pseudofirmus bacteria at a concentration of 108 cells/ml into three fine lightweight aggregate samples. In these samples, three different nutrients namely, magnesium acetate; calcium lactate; and sodium lactate were added to yeast extract and impregnated at a concentration of 75 mM/l along with the bacteria. Eventually, Scanning Electron Microscope with Energy Dispersive Spectroscopy analysis (SEM-EDS analysis) was conducted to evaluate the impregnation efficiency of the bacteria into the three aggregate samples. The results indicated that the bacteria were successfully impregnated into all the aggregate samples. Future work will be conducted in this study to evaluate the pre-cracking strength recovery and crack sealing efficiency for the different nutrients.

Publication Source (Journal or Book title)

Tran-SET 2021 - Proceedings of the Tran-SET Conference 2021

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