微生物矿化对C3S硬化浆体表层微观结构的影响  

Effects of microbial mineralization on microstructure of surface layer in hardened C3S paste

作　　者：王潇猛 钱春香[1,2] 陈燕强 曲军 郭景强 刘江虹 Wang Xiaomeng;Qian Chunxiang;Chen Yanqiang;Qu Jun;Guo Jingqiang;Liu Jianghong(School of Materials Science and Engineering,Southeast University,Nanjing 211189,China;Research Center of Green Building and Construction Materials,Southeast University,Nanjing 211189,China;Sika China,Suzhou 215121,China)

机构地区：[1]东南大学材料科学与工程学院,南京211189 [2]东南大学绿色建材研究中心,南京211189 [3]西卡(中国)有限公司,苏州215121

出　　处：《东南大学学报（自然科学版）》2020年第6期1023-1029,共7页Journal of Southeast University：Natural Science Edition

基　　金：国家自然科学基金重点资助项目(51738003).

摘　　要：为揭示微生物矿化对水泥基材料表层微观结构的影响,采用水泥中主要成分C3S与微生物拌和进行水化矿化试验.分别采用恒温量热仪和X射性衍射定量分析对C3S硬化浆体水化热及水化程度进行表征,并通过X射线衍射仪、扫描电镜、能谱仪和纳米压痕对硬化浆体中矿化产物及水化产物的钙硅比和弹性模量进行测量.结果表明:矿化作用加速了C3S的早期水化速率,提高了早期水化程度;矿化作用产生了晶型主要为方解石的碳酸钙,并降低了C-S-H凝胶的钙硅比,并使高密度和低密度C-S-H弹性模量不再明显区分;试件表层不同深度处Ca(OH)2和CaCO3含量随深度呈现梯度分布,Ca(OH)2含量随深度逐渐增大,CaCO3含量随深度逐渐减小;矿化降低了试件表层1~6 mm处总孔隙率和连通孔隙率,使平均孔径从70μm降低至40~50μm.To reveal the effects of microbial mineralization on the surface microstructure of cement-based materials,a hydration-mineralization test was carried out by mixing the C3S powder which was the main component of cement-based materials with microorganisms.The thermostatic calorimeter and quantitative X-ray diffractometry(QXRD)were used to characterize the hydration heat and the hydration degree of C3S hardened paste.The calcium-silicon ratio and the elastic modulus of the mineralized and hydrated products in the hardened paste were measured by X-ray diffractometer(XRD),scanning electron microscope(SEM),energy disperse spectroscopy(EDS),and nanoindentation.The results show that the microbial mineralization accelerates the early hydration of C3S and increases the degree of the early hydration.The mineralization produces the calcium carbonate whose crystal type is mainly calcite,reduces the calcium-silicon ratio of the hydration product C-S-H gel,and changes its elastic modulus,so that the elastic modulus of high-density and low-density C-S-H is no longer clearly distinguished.The contents of Ca(OH)2 and CaCO3 at different depths on the surface of the specimen show a gradient distribution with the depth.The content of Ca(OH)2 gradually increases with the depth,and the content of CaCO3 decreases with the depth.The progress of the mineralization reduces the total porosity and the connected porosity in the surface layer of the specimen at 1-6 mm,and the average pore size is reduced from 70μm to 40-50μm.

关 键 词：微生物矿化 水化 微观力学 表层强化 孔结构 

分 类 号：TU526[建筑科学—建筑技术科学]