Influence of Induced Bacteria Cell on the Strength Properties of Concrete
Saad Issa Sarsam1*, Likaa Hamied Mahdi2, Mohamed Fadhel Suliman3, Hala Ayad Ali2
1Department of Civil Engineering, College of Engineering, University of Baghdad, Iraq.
2Department of Biology, College of Science, University of Al-Mustansiriayah, Iraq
3MSc. Student, Department of Highway & Transportation, College of Engineering, University of Al-Mustansiriayah, Iraq.
In the recent years, Microbiologically Induced Calcium Carbonate Precipitation (MICCP) by the bacteria is considered as an environment friendly method to enhance the properties of concrete, as well as to repair the cracking of concrete structure. This work deals with the novel technique of self-healing of cracks in concrete by the microbial induced calcite precipitation in concrete by the bacteria Bacillus subtilis. Bacillus subtilis is added to the mixing water in the making of concrete in the concentration of 106 cell/ml. During the crack formation through shrinkage process, these bacteria get activated due to its exposure to the air and water. The bacteria start taking its food from calcium lactate and reacting with cement particles then emits CaCO3 by the process of Bio calcification. Two groups of concrete specimens (cube, cylinder, and beams) have been prepared in the laboratory; the first group was the control mix, while the second group was the bacterial concrete mix. Specimens have been tested for strength properties determination (compressive, indirect tensile, and flexural). Test results were compared with those of control mix. It was concluded that implementation of induced bacteria cell into the mixing water of concrete exhibit positive impact on the strength properties of concrete.
Key words: Bacterial concrete, Bacillus subtilis, self-healing, strength, MICCP.