微生物矿化抑制碱-硅酸反应的试验与机制探索  

Experimental and mechanism exploration of alkali-silica reaction inhibition by microbial mineralization

作　　者：郑玉龙 林鸿儒 陆春华[1] 王景全 ZHENG Yulong;LIN Hongru;LU Chunhua;WANG Jingquan(Faculty of Civil Engineering Mechanics,Jiangsu University,Zhenjiang 212013,China)

机构地区：[1]江苏大学土木工程与力学学院,镇江212013

出　　处：《复合材料学报》2024年第8期4225-4235,共11页Acta Materiae Compositae Sinica

基　　金：国家自然科学基金项目(52108147,51878319);江苏省博士后科研资助计划(2020Z350);江苏大学高级人才基金(20JDG19)。

摘　　要：碱-硅酸反应(ASR)是混凝土中碱性孔隙溶液和骨料中反应性非结晶SiO2之间的反应,会导致混凝土膨胀和开裂及力学性能下降。本文基于巴氏芽孢杆菌微生物诱导碳酸钙沉淀(MICP)技术,采用不同处理次数及方式(表面处理潜在活性骨料及其制成的砂浆棒),综合评价MICP对ASR的抑制规律与机制。结果表明:MICP处理可以在骨料及砂浆棒表面形成具有黏附作用的致密CaCO_(3)层,从而阻止碱性离子和水的入侵,且抑制效果随处理次数的增多而变强;与对照组相比,处理砂浆棒时,力学性能最大提升了13.8%,膨胀率下降了35%;处理骨料时,由于表面CaCO_(3)层可同时阻隔孔隙溶液中已有及外部入侵的碱性离子与水分,其力学性能提升了25.3%,膨胀率下降了59.6%,具有更好的抑制效果。微观结构和成分分析表明,经MICP处理后骨料表面Si和Na原子比例分别下降了69.6%和88.9%,表明ASR凝胶显著减少。Alkali-silica reaction(ASR)is a reaction between alkaline pore solutions in concrete and reactive noncrystalline SiO2 in aggregates,which leads to expansion and cracking of the concrete,and degradation of mechanical properties.In this study,based on the microbial induced calcium carbonate precipitation(MICP)technique of Bacillus pasteurus,various treatment frequencies and methods,including surface treatments of potentially active aggregates and mortar bars made by them,to comprehensively evaluate the inhibition law and mechanism of MICP on ASR.The results showed that the MICP treatment could form a dense CaCO_(3)layer with adhesive effect on the surface of aggregates and mortar bars,thus preventing the intrusion of alkaline ions and water,and the inhibiting effect became stronger with the treatment numbers.Compared with the control group,the maximum increase in mechanical properties of 13.8%,and the decrease in expansion rate of 35%were observed when the mortar bars were treated.When treating the aggregate,the mechanical properties were improved by 25.3%and the expansion rate was reduced by 59.6%with a better inhibition effect,as the surface CaCO_(3)layer could simultaneously block the alkaline ions and water existing in the pore solution and invading from outside.Microstructural and compositional analyses showed that the proportion of Si and Na atoms on the aggregate surface decreased by 69.6%and 88.9%,respectively,after treatment,indicating a significant reduction in the ASR gel.

关 键 词：MICP 碱-硅酸反应 锦屏砂岩 力学性能 膨胀率 

分 类 号：TU528[建筑科学—建筑技术科学] TB332[一般工业技术—材料科学与工程]