Effect of Corrosive Ions (Cl^-,SO4^2-,and Mg^2+) on the Nanostructure and Chloride Binding Property of C-A-S-H Gel  

作　　者：JIN Shucheng LIU Kai ZHANG Gaozhan SHI Hua DING Qingjun XU Wenyuan JIN Shucheng;LIU Kai;ZHANG Gaozhan;SHI Hua;DING Qingjun;徐文远(School of Civil Engineering,Northeast Forestry University,Harbin 150040,China;China Construction Ready Mixed Concrete Co.,Ltd,Wuhan 430200,China;School of Materials and Chemical Engineering,Anhui Jianzhu University,Hefei 230601,China;School of Materials Science and Engineering,Wuhan University of Technology,Wuhan 430070,China)

机构地区：[1]School of Civil Engineering,Northeast Forestry University,Harbin 150040,China [2]China Construction Ready Mixed Concrete Co.,Ltd,Wuhan 430200,China [3]School of Materials and Chemical Engineering,Anhui Jianzhu University,Hefei 230601,China [4]School of Materials Science and Engineering,Wuhan University of Technology,Wuhan 430070,China

出　　处：《Journal of Wuhan University of Technology(Materials Science)》2020年第6期1061-1072,共12页武汉理工大学学报（材料科学英文版）

基　　金：Funded by the Key Science and Technology Project of Heilongjiang Transport Department(No.2017HLJ0029);the National Natural Science Foundation of China(Nos.51778513 and 51878003);the Key Projects of Anhui Province Outstanding Young Talents Support Plan(gxyqZD2019055)。

摘　　要：The nanostructure and chloride binding capacity evolution of C-A-S-H gel exposed to aggressive solutions were investigated,utilizing 29Si NMR,27Al NMR,SEM-EDS,and XRD techniques.The experimental results show that while Cl-ions show a smaller effect on the microstructure of C-A-S-H sample,and SO4^2-ions can react with C-A-S-H,resulting in decreasing Ca/Si and Al[4]/Si for the C-A-S-H gel (i e,decalcification and dealuminization).The presence of Mg^2+ ions can aggravate the decalcifying and dealuminizing effects of SO4^2-ions on the C-A-S-H.With decreasing Ca/Si ratio and aluminum substitution for the original C-A-S-H gel,the depolymerization degree of silicate tetrahedra increases and the calcium aluminosilicate skeleton strengthens.C-A-S-H gel with lower Ca/Si ratio and higher Al[4]/Si ratio shows gentler nanostructure evolution under chemical attack,i e,improving thermodynamic stability under chemical attack.Furthermore,the chloride binding capacity of C-A-S-H gel is decreased after the sulfate attack.Aluminum substitution can also help C-A-S-H gel resist the degraded chloride binding capacity induced by sulfate attack.

关 键 词：calcium-silicate-hydrate ions attack Ca/Si ratio /Si aluminum uptake 

分 类 号：TB304[一般工业技术—材料科学与工程]