Laboratory analysis of self-healing cement composition based on calcium lactate and bacteria

The research aims to evaluate the feasibility of using bacteria-based self-healing concrete using Portland cement and assess the effect of temperature on its performance. The results showed that the inclusion of calcium lactate and bacteria in the mixture accelerates the gain in compressive strength, but after 28 days of curing, the healing agent has no impact on the overall compressive strength value of the mixture. The crack width distribution analysis revealed an inverse relationship between crack width and self-healed area, with wider cracks having lower self-healing rates. Most of the healing occurs within 15 days, with only a small fraction healing between day 15 and 60 days. The study also showed that low temperatures do not produce self-healing in tested samples, and 25 degrees C increases the self-healed area for all crack widths. Finally, chromatography tests of submerged water reveal that reaction to seal the cracks takes calcium from some external source.