As a new concrete crack patching technology, microbial self-healing slurries offer favourable characteristics including non-pollution, ecological sustainability and good compatibility with concrete. In this paper, a nano-sio2-modified microbial bacteria liquid, combined with sodium alginate and polyvinyl alcohol, was used to prepare a nano-modified microbial self-healing slurry. This slurry was used to coat concrete under negative pressure in order to verify its restoration effect, and the micromorphology of the resulting microbial mineralization products was observed. The results revealed that patching the concrete using the nano-modified microbial slurry significantly improved its permeability, and increased its carbonization resistance by three times in comparison with the control group. Through a combination of Scanning electron microscopy (SEM) and X-ray diffraction (XRD) observation, it was determined that the microbial mineralization reaction products were mainly calcite crystals, which, integrated with the nano-sio2, sodium alginate and polyvinyl alcohol at the microscopic level, filled the internal pores of concrete, thus improving its durability. • Surface crack treatment of concrete using a nano-modified microbial slurry was investigated. • Patching concrete using nano-microbial slurry clearly improved its chloride penetration. • The carbonization of the concrete was three times in comparision with the control group. • The main product of the microbial mineralization reaction was calcite crystal.

中文翻译：

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纳米改性微生物碳酸盐沉淀处理混凝土表面裂缝

微生物自修复浆料作为一种新型混凝土裂缝修补技术，具有无污染、生态可持续性、与混凝土相容性好等优点。本文采用纳米SiO2改性微生物菌液，与海藻酸钠和聚乙烯醇复合，制备纳米改性微生物自修复浆料。使用该浆料在负压下涂覆混凝土以验证其修复效果，并观察所得微生物矿化产物的微观形貌。结果表明，使用纳米改性微生物浆料修补混凝土，其渗透性显着提高，抗碳化能力较对照组提高了三倍。通过扫描电子显微镜（SEM）和X射线衍射（XRD）观察相结合，确定微生物矿化反应产物主要为方解石晶体，其与纳米SiO2、海藻酸钠和聚乙烯醇在微观层面，填充混凝土内部孔隙，从而提高其耐久性。• 研究了使用纳米改性微生物浆料对混凝土进行表面裂缝处理。• 使用纳米微生物浆料修补混凝土明显提高了其氯离子渗透率。• 混凝土的碳化程度是对照组的三倍。• 微生物矿化反应的主要产物是方解石晶体。