Use of Methylcellulose-Based Pellet to Enhance the Bacterial Self-Healing of Cement Composite

In this study, a new type of bacterial carrier using methylcellulose was presented, and its applicability to self-healing concrete has been explored. Methylcellulose, the main component of a 2 mm pellet-shaped carrier, can remain stable in alkaline environments and expand in neutral or acidic environments. These properties allow bacteria to survive in the high-alkaline and high-pressure environments of early age concrete, and the number of bacteria increases rapidly in the event of cracks, accelerating crack closure. The results show that the survival rate of bacterial spores inside the mortar was increased, and the pellet provides an enhanced biological anchor suitable for bacterial activity, bacterial growth, and mineral precipitation. Further, the results indicate an improved self-healing efficiency compared with mixing bacteria directly into the cement composite.