Development of Bacterium for Crack Healing and Improving Properties of Concrete under Wet–Dry and Full-Wet Curing

Arunachalam Sumathi, Gunasekaran Murali, Dharmalingam Gowdhaman, Mugahed Amran, Roman Fediuk, Nikolai Ivanovich Vatin, Ramamurthy Deeba Laxme, Thillai Seenu Gowsika
2020 Sustainability  
Concrete cracking is inevitable, coupled with increased permeability, exacerbating the adverse impacts of atmospheric conditions and chemical attacks. Calcium carbonate precipitation resulting from certain microorganisms' metabolism is a novel approach that can self-heal the cracks and improve concrete properties. In this study, the development and effect of bacteria Bacillus cohnii on crack healing, regained compressive strength after pre-cracking, sorptivity, water absorption, and concrete
more » ... on, and concrete microstructures were investigated. For this purpose, a Bacillus cohnii bacterial concentration of 105 cells/mL was used as a water replacement in the concrete mixtures. Two methods subsequently cured the prepared concrete specimens: wet–dry (W-D) cycle and full-wet (F-W). In the wet–dry cycle, the cast specimens were immersed in water for 24 h and then kept at room temperature for 24 h, which was considered as one cycle; this process was repeated for 28 days. In the full-wet curing, specimens were immersed in water for 28 days. However, the curing water was changed every 24 h to facilitate the essential oxygen supply for bacterial activity to precipitate calcium carbonate. The results revealed that 90% and 88% surface healing was noticed in full-wet and full-dry pre-cracked specimens at 28 days.
doi:10.3390/su122410346 fatcat:5grx3x7ukjctxgwkdmlrkq44lu