海水环境下混凝土裂缝微生物改性修复研究  

Study on Microbial Modification of Concrete Cracks in Seawater Environment

作　　者：熊雨 肖瑶[1] 邓华锋[1] 李建林[1] 黄叶宁 朱文羲 XIONG Yu;XIAO Yao;DENG Huafeng;LI Jianin;HUANG Yening;ZHU Wenxi(Key Laboratory of Geological Hazards on Three Gorges Reservoir Area of Ministry of Education,China Three Gorges University,Yichang 443002,China)

机构地区：[1]三峡大学,三峡库区地质灾害教育部重点实验室,湖北宜昌443002

出　　处：《应用基础与工程科学学报》2024年第1期160-177,共18页Journal of Basic Science and Engineering

基　　金：国家自然科学基金项目(U2034203,U22A20600);湖北省自然科学基金创新群体项目(2020CFA049)。

摘　　要：为了提升海水环境下混凝土裂缝的MICP修复效果,以火山灰作为固菌载体,进行了海水环境下火山灰增强MICP修复混凝土裂缝试验,综合修复体的宏观物理力学试验和微细观检测,系统分析了火山灰对MICP技术修复混凝土裂缝的影响及作用机制.结果表明,(1)经过海水驯化的巴氏芽孢杆菌对海水环境适应性增强,胶结物产量明显提升;(2)火山灰能够有效提升MICP对混凝土裂缝的修复效果,加固试样的抗剪强度,提升了75.12%~94.94%,抗压强度增加了50.36%,渗透系数从10^(-2)cm/s降低至10^(-7)cm/s,超声波检测的声时值降低了48.52%~49.16%;(3)火山灰对MICP修复混凝土裂缝的改性增强作用机制主要包括3方面:第一方面,火山灰对菌体的保护作用,火山灰中的活性氧化物与强碱发生反应,消耗环境中的OH~-,降低裂缝内的pH值,同时火山灰的多孔结构使细菌的“定植区域”增加,为其提供较适宜的生长反应环境;第二方面,火山灰自身作为填充物优化了裂缝空间结构,使其密实性增加;第三方面,火山灰的水化反应和聚合反应生成了碳酸盐-硅铝酸盐等复合凝胶体,使混凝土裂缝的修复效果进一步提升.In order to improve the repairing effect under seawater,test of using pozzolan as carrier to enhance MICP technology on concrete cracks was carried out.The macroscopic physical and mechanical test and microscopic detection of the restoration were combined to systematically analyze the influence and mechanism of pozzolan on MICP technology repairing concrete cracks.The results show as following:(1)The adaptability of sporosarcina pasteuri domesticated by seawater was obviously enhanced,and the cement production increased significantly.(2)The addition of pozzolan could significantly improve the repairing effect of MICP on concrete cracks.The shear strength of reinforced samples increased by 75.12%~94.94%,while the compressive strength increased by 50.36%.Meanwhile,the permeability coefficient decreased from 10^(-2)cm/s to 10^(-7)cm/s,and the acoustic time value decreased by 48.52%~49.16%.(3)The enhancement mechanism of pozzolan on MICP repairing concrete cracks mainly includes three aspects:First,bacteria could be protected by the pozzolan,which contained active oxides that could react with strong base to consume OH and reduce the pH value in the fractures.In the meantime,the porous structure of pozzolan can increase the"colonization area"of bacteria and provide a suitable growth environment.Second,the pozzolan itself as a filler optimizes the crack space structure and increases its compactness.Third,the hydration and polymerization reactions of pozzolans generated carbonate-aluminosilicate and other composite gels,which further improved the repairing effect of concrete cracks.

关 键 词：海水环境 MICP 海水驯化巴氏芽孢杆菌 火山灰 裂缝修复 抗压强度 X射线衍射 SEM 增强机制 

分 类 号：TU528[建筑科学—建筑技术科学]