摘要
活性生物泥是基于微生物诱导碳酸钙沉淀(microbial-induced calcium carbonate precipitation,简称MICP)技术生成,由碳酸钙和嵌入其中的脲酶菌组成的具备脲酶活性的泥状混合物。提出了活性生物泥修复破损文物砖的方法,开展了仿真文物砖缺口修复的室内试验和PFC^(2D)数值模拟,研究了修复砖块的力学响应和微观结构,评估了该方法的可行性,并对修复机制和受荷破裂机制进行了分析。结果表明:活性生物泥能够对缺口仿真文物砖进行有效修复,其修复效果受养护时间和缺口深度影响。养护时间越长,缺口深度越浅,修复后试样的抗弯强度越高。修复后缺口处碳酸钙的结构分析表明:浸泡养护后的活性生物泥可形成外层和内层碳酸钙,外层碳酸钙以大小10~25μm菱形颗粒为主,而内层以5μm左右的球型颗粒为主,形成两层碳酸钙结构的原因可能由于扩散至活性生物泥内外层的钙离子和尿素浓度差异引起的。养护1、3、5 d后外层碳酸钙厚度分别为2~2.5、3~4、4~5 mm。PFC^(2D)数值试验显示内层碳酸钙的细观力学参数约为外层的0.1倍。试验和数值模拟均表明修复后仿真砖的抗弯强度增长主要由外层碳酸钙贡献。PFC^(2D)数值模拟进一步显示,修复仿真砖受弯折荷载时,裂缝从内层碳酸钙开始并逐渐扩展至整个碳酸钙层和未损伤砖体。研究不仅拓展了微生物加固技术的应用范围,也为文物砖修复提供了新的思路。
The active bioslurry,a urease-active slurry mixture composed of calcium carbonate and embedded urease-producing bacteria,is generated using microbial-induced calcium carbonate precipitation(MICP)technology.This study proposes a method for heritage bricks restoration using active bioslurry.Laboratory experiments and PFC^(2D) numerical simulations were conducted on notched simulated bricks to examine the mechanical response and microstructure of the repaired bricks and evaluate the feasibility of this method.Additionally,the repair and failure mechanisms under load were analyzed.The results show that active bioslurry effectively repairs notched simulated heritage bricks,with effectiveness influenced by curing time and notch depth.Longer curing time and shallower notch result in higher flexural strength of repaired samples.Analysis of the structure of calcium carbonate in the repaired notches indicates that after immersion curing,active bioslurry forms two layers of calcium carbonate:an outer layer of rhombohedral particles(approximately 10−25mm),and an inner layer of spherical particles(around 5mm).This two-layer structure likely results from differences in calcium ion and urea concentrations diffusing into the inner and outer layers of bioslurry.After 1,3,and 5 days of curing,the thickness of the outer calcium carbonate layer was 2−2.5 mm,3−4 mm,and 4−5 mm,respectively.PFC^(2D) numerical simulations indicate that the micromechanical parameters of the inner calcium carbonate layer are approximately 0.1 times those of the outer layer.Experimental and numerical simulation results demonstrate that the increase in flexural strength of the repaired simulated bricks is primarily attributed to the outer calcium carbonate layer.PFC^(2D) simulations further show that when the repaired bricks are subjected to bending loads,cracks initiate in the inner calcium carbonate layer and gradually propagate through the entire calcium carbonate layer and the undamaged brick body.This study not only expands the application scope of microbial reinforcement technology but also provides new insights for the restoration of heritage bricks.
作者
杨阳
张程
何想
张建伟
陈育民
叶琳
武发思
张涵
YANG Yang;ZHANG Cheng;HE Xiang;ZHANG Jian-wei;CHEN Yu-min;YE Lin;WU Fa-si;ZHANG Han(School of Civil Engineering,Chongqing University,Chongqing 400045,China;Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering,Hohai University,Nanjing,Jiangsu 210098,China;School of Civil Engineering and Architecture,Henan University,Kaifeng,Henan 475000,China;School of Civil Engineering,Suzhou University of Science and Technology,Suzhou,Jiangsu 215011,China;Chongqing Cultural Relics and Archaeology Research Institute,Chongqing 400013,China;National Research Center for Conservation of Ancient Wall Paintings and Earthen Sites,Dunhuang Academy,Dunhuang,Gansu 736200,China)
出处
《岩土力学》
北大核心
2025年第6期1777-1787,共11页
Rock and Soil Mechanics
基金
国家自然科学基金(No.52478326)
河海大学岩土力学与堤坝工程教育部重点实验室开放基金(No.2021009)
重庆市科研机构绩效激励引导专项(No.CSTB2023JXJL-YFX0081)。
关键词
活性生物泥
文物砖
微生物诱导碳酸钙沉淀(MICP)
碳酸钙
脲酶菌
active bioslurry
heritage bricks
microbial-induced calcium carbonate precipitation(MICP)
calcium carbonate
urease-producing bacteria
