Bacterial concrete is a promising self-healing alternative due to its ability to seal cracks. However, to ensure effective self-healing, bacteria must be protected from the harsh conditions within concrete. This study examines the self-healing efficiency of bacterial concrete utilizing cationic cellulose nanocrystals (cCNCs) to immobilize Bacillus pseudofirmus bacteria. The study examined the effect of different combinations of precursors (magnesium acetate, calcium lactate, and sodium lactate); bacteria (with or without bacteria); and cCNC content on the mechanical properties and self-healing efficiency of mortars. Compressive strength, flexural strength, healing efficiencies, and scanning electron microscopy (SEM) tests were performed to characterize the properties of the bacterial mixes. Experimental results showed that the mixture using calcium lactate with bacteria had the best self-healing efficiency of 71% and 64% for side and bottom cracks, respectively. The same mixture and the mixture including calcium lactate without bacteria yielded the highest compressive strength. The mixture with 2 wt.% cCNC content demonstrated the highest recovery of flexural strength with a value of 49%. Based on the results, it can be concluded that bacterial concrete’s mechanical properties and self-healing can be optimized using bacteria protected by cCNC and calcium lactate (as a precursor).
Gavilanes et al. (Thu,) studied this question.