Ivaškė Augusta, Gribniak Viktor, Jakubovskis Ronaldas, Urbonavičius Jaunius
Department of Chemistry and Bioengineering, Faculty of Fundamental Sciences, Vilnius Gediminas Technical University (VILNIUS TECH), Saulėtekio al. 11, 10223 Vilnius, Lithuania.
Laboratory of Innovative Building Structures, Faculty of Civil Engineering, Vilnius Gediminas Technical University (VILNIUS TECH), Saulėtekio al. 11, 10223 Vilnius, Lithuania.
Microorganisms. 2023 Sep 26;11(10):2402. doi: 10.3390/microorganisms11102402.
Cracking is an inevitable feature of concrete, typically leading to corrosion of the embedded steel reinforcement and massive deterioration because of the freezing-thawing cycles. Different means have been proposed to increase the serviceability performance of cracked concrete structures. This case study deals with bacteria encapsulated in cementitious materials to "heal" cracks. Such a biological self-healing system requires preserving the bacteria's viability in the cement matrix. Many embedded bacterial spores are damaged during concrete curing, drastically reducing efficiency. This study investigates the viability of commonly used non-ureolytic bacterial spores when immobilized in calcium alginate microcapsules within self-healing cementitious composites. Three species were used in this study, i.e., , , and . demonstrated the best mineralization activity; a sufficient number of bacterial spores remained viable after the encapsulation. and spores retained the highest viability after incorporating the microcapsules into the cement paste, while spores retained the highest viability in the mortar. Cracks with a width of about 0.13 mm were filled with bacterial calcium carbonate within 14 to 28 days, depending on the type of bacteria. Larger cracks were not healed entirely. had the highest efficiency, with a healing coefficient of 0.497 after 56 days. This study also revealed the essential role of the cement hydration temperature on bacterial viability. Thus, further studies should optimize the content of bacteria and nutrients in the microcapsule structure.
开裂是混凝土不可避免的特性，通常会导致埋入的钢筋腐蚀，并因冻融循环而严重劣化。人们提出了不同的方法来提高开裂混凝土结构的使用性能。本案例研究涉及将细菌封装在胶凝材料中以“修复”裂缝。这种生物自修复系统需要保持细菌在水泥基质中的活力。许多嵌入的细菌孢子在混凝土固化过程中受损，大大降低了效率。本研究调查了常用的非尿素分解细菌孢子固定在自修复胶凝复合材料中的海藻酸钙微胶囊内时的活力。本研究使用了三种菌种，即[具体菌种1]、[具体菌种2]和[具体菌种3]。[具体菌种1]表现出最佳的矿化活性；封装后仍有足够数量的细菌孢子保持活力。将微胶囊掺入水泥浆体后，[具体菌种2]和[具体菌种3]的孢子保持了最高的活力，而[具体菌种3]的孢子在砂浆中保持了最高的活力。宽度约为0.13毫米的裂缝在14至28天内被细菌碳酸钙填充，具体时间取决于细菌类型。较大的裂缝没有完全愈合。[具体菌种1]效率最高，56天后愈合系数为0.497。本研究还揭示了水泥水化温度对细菌活力的重要作用。因此，进一步的研究应优化微胶囊结构中细菌和养分的含量。
