Wang Yan-Sheng, Zhou Yi-Ze, Wang Xu-Dong, Zhang Guang-Zhu
School of Civil Engineering and Transportation, Northeast Forestry University, Harbin 150040, China.
College of Catholic, Songsim Global Campus, The Catholic University of Korea, Bucheon-si 14662, Republic of Korea.
Materials (Basel). 2025 May 12;18(10):2245. doi: 10.3390/ma18102245.
Negative temperature environments inhibit bacterial survival in cementitious materials and reduce the self-healing ability of bacteria. To address this challenge, acid-etched alumina hollow spheres are proposed as carriers to encapsulate microorganisms in cementitious materials. The effects of these carriers on the mechanical properties, thermal conductivity, self-healing properties, and self-healing products of specimens after exposure to -20 °C were investigated. Finally, the self-healing mechanism was examined and analyzed. The results demonstrated the effectiveness of the acid-etched hollow microbeads as bacterial carriers. The addition of the alumina hollow spheres participating in the cement hydration reaction enhanced the mechanical properties of the mortar and reduced its thermal conductivity, which supported bacterial survival in the negative temperature environment. Although negative temperature environments may reduce bacterial populations, the hydrolysis of aluminum ions in the alumina hollow spheres during bacterial metabolism resulted in the precipitation of aluminum hydroxide flocs. These flocs adsorbed free calcium carbonate in the pores, converting it into effective calcium carbonate with cementing properties, thus enhancing the crack healing capability of the examined specimens. This microbe-based self-healing strategy, utilizing alumina hollow spheres as bacterial carriers, is anticipated to provide an effective solution for achieving efficient crack self-healing in mortars that is resistant to the detrimental effects of negative temperature conditions.
负温度环境会抑制细菌在胶凝材料中的存活，并降低细菌的自我修复能力。为应对这一挑战，提出了用酸蚀氧化铝空心球作为载体，将微生物封装在胶凝材料中。研究了这些载体对试件在暴露于-20℃后的力学性能、热导率、自我修复性能和自我修复产物的影响。最后，对自我修复机理进行了研究和分析。结果证明了酸蚀空心微珠作为细菌载体的有效性。参与水泥水化反应的氧化铝空心球的添加增强了砂浆的力学性能并降低了其热导率，这有助于细菌在负温度环境中存活。尽管负温度环境可能会减少细菌数量，但在细菌代谢过程中氧化铝空心球中的铝离子水解会导致氢氧化铝絮凝物沉淀。这些絮凝物吸附孔隙中的游离碳酸钙，将其转化为具有胶结性能的有效碳酸钙，从而增强了受试试件的裂缝愈合能力。这种以微生物为基础的自我修复策略，利用氧化铝空心球作为细菌载体，有望为实现砂浆中高效的裂缝自我修复提供一种有效的解决方案，使其能够抵抗负温度条件的不利影响。
