| 孟永东,徐晓蔚,丁毅,王宇,蔡征龙,田斌.适宜水工混凝土内环境的矿化微生物梯度驯化优选[J].水利学报,2024,55(6):698-710 |
| 适宜水工混凝土内环境的矿化微生物梯度驯化优选 |
| Gradient domestication and selection of mineralizing microorganisms suitable for the internal environment of hydraulic concrete |
| 投稿时间：2023-12-01 |
| DOI：10.13243/j.cnki.slxb.20230753 |
| 中文关键词: 水工混凝土 裂缝自修复 矿化微生物 梯度驯化 微观分析 |
| 英文关键词: hydraulic concrete cracks self-repairing mineralized microorganisms gradient domestication micro analysis |
| 基金项目:国家自然科学基金面上项目(52179137) |
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| 中文摘要: |
| 水工混凝土内部高碱性环境限制了微生物混凝土的自修复效能。利用梯度驯化方法可提高矿化微生物对高碱度的耐受性，优选出适宜混凝土孔隙内环境并具备高诱导矿化沉积能力的增强嗜碱型微生物。首先，在实验室高碱性环境下，对比巨大、科氏、枯草、巴氏等4种芽孢杆菌的活性及诱导矿化沉积量，初选耐碱性较好的微生物并对其开展耐碱性梯度驯化;随后，综合分析驯化微生物对混凝土力学性能、吸水性、渗透性和自愈能力的影响，通过扫描电子显微镜和X射线衍射对矿化产物微观形态和组成进行分析。结果表明：相较于巨大、科氏和枯草芽孢杆菌，巴氏芽孢杆菌在高碱性条件下表现出更强的活性，梯度驯化技术可进一步提高巴氏芽孢杆菌在高碱性环境中的活性，并证实通过该方法增强的耐碱性具有后代保留的特性;与掺未驯化微生物组试样相比，掺驯化微生物混凝土试样养护28 d的抗压强度提高了16.59%，吸水系数降低了37.74%，渗透系数减小了19.22%;掺驯化微生物混凝土试样的裂缝自修复试验得到裂缝最大修复宽度为0.57 mm，超过了未驯化微生物组的0.44 mm。本研究为基于微生物诱导矿化沉积技术的微生物水工混凝土研发和应用提供理论依据和技术支撑。 |
| 英文摘要: |
| The harsh alkaline conditions within the internal structure of hydraulic concrete constrain the self-healing efficacy of microbial concrete.This study employs a gradient domestication method to enhance the alkaline tolerance of mineralized microorganisms，selecting enhanced alkaliphilic microorganisms that are well-suited to the pore environment of concrete and possess a heightened capacity for inducing mineralization deposition.Initially，under high alkaline conditions in laboratory，the activity and induced mineralization deposition of four Bacillus species(B.megaterium，B.cohnii，B.subtilis，and B.pasteurii) were compared.Microorganisms exhibiting superior alkaline resistance were preliminarily selected，and an adaptive alkaline tolerance domestication process was conducted.Subsequently，a comprehensive investigation of the impact of domesticated microorganisms on concrete mechanical properties，capillary water absorption，water permeability，and self-healing capability was undertaken.Scanning electron microscopy and X-ray diffraction techniques were employed for the characterization of the microscopic morphology and composition of mineralized products.The results indicate that，in comparison to B.megaterium，B.cohnii，and B.subtilis，B.pasteurii demonstrates higher activity under high alkaline conditions.The gradient domestication technique further enhances the activity of B.pasteurii in high alkaline environments，confirming that the enhanced alkaline resistance through this method exhibits multigenerational retention characteristics.In comparison to the 28-day unmodified microbial samples，the compressive strength of concrete incorporating domesticated microorganisms increased by 16.59%，and water absorption decreased by 37.74%.Additionally，the maximum closed crack width was 0.57 mm，exceeding the 0.44 mm of the unmodified bacterial group.Compared to unmodified bacterial samples，the water permeability coefficient of domesticated bacterial samples decreased by 19.22% at 28 days.This research provides a viable strategy for improving the efficiency of microbial-induced calcium carbonate precipitation in concrete. |
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