Concomitant Participation of Bacteria, Metakaolin, and Calcium Lactate to Improve Concrete Durability and Surface Crack Healing

Abstract

Bacteria-based self-healing concrete with simultaneous application of calcium lactate as bacteria precursor, and metakaolin as cement replacement, was investigated to observe its behavior under inappropriate environmental conditions and microstructural change. Samples of weight loss, compressive strength, stereoscope photography, and scanning electron microscope (SEM) imaging were studied after water curing and acid immersion. Increase in the compressive strength due to the addition and increase in the amount of calcium lactate and decrease of compressive strength by presence of metakaolin were observed. Application of calcium lactate and bacteria in the concrete with metakaolin decreased strength reduction and even resulted in a higher strength than the ordinary concrete. Metakaolin was effective to improve concrete resistance against acid attack. However, the concomitant role of calcium lactate as a precursor for bacteria in concrete that led to surface crack healing, even after 1 year, with metakaolin as a cement replacement component, can be supportive to produce a durable biofriendly concrete.