基于第一性原理的不同侵蚀性离子作用下混凝土孔溶液中钢筋腐蚀机理  

Corrosion Mechanism of Reinforcement Subjected to Different Corrosive Ions in Concrete Pore Solution Based On First-Principles

作　　者：农喻媚 陈正[1,2] 陈晔 韦增硕 李静 王一琛[1] 庞兰 NONG Yumei;CHEN Zheng;CHEN Ye;WEI Zengshuo;LI Jing;WANG Yichen;PANG Lan(Key Laboratory of Disaster Prevention and Structural Safety of Ministry of Education,Guangxi University,Nanning 530004,China;Guangxi Key Laboratory of Disaster Prevention and Structural Safety,Guangxi University,Nanning 530004,China;School of Resources,Environment and Materials,Guangxi University,Nanning 530004,China)

机构地区：[1]广西大学工程防灾与结构安全教育部重点实验室,南宁530004 [2]广西大学广西防灾减灾与工程安全重点实验室,南宁530004 [3]广西大学资源环境与材料学院,南宁530004

出　　处：《硅酸盐学报》2023年第5期1191-1201,共11页Journal of The Chinese Ceramic Society

基　　金：国家自然科学基金项目(U2006224);广西自然科学基金项目(2022GXNSFFA035035);广西大学学科交叉科研项目(2022JCC016)。

摘　　要：为了揭示Cl^(-)、SO_(4)^(2-)作用下混凝土中钢筋腐蚀机理的差异,并为氯盐和硫酸盐侵蚀下混凝土的抗腐蚀调控提供理论基础,研究了Cl^(-)、SO_(4)^(2-)侵蚀下混凝土孔溶液中钢筋的电化学行为差异,并利用基于第一性原理的密度泛函理论研究了腐蚀性物质(Cl^(-)、SO_(4)^(2-))和致钝物质(CaOH^(+)、OH^(-))在Fe(100)表面的竞争吸附.结果表明:相较于含Cl^(-)的混凝土孔溶液,钢筋在含SO_(4)^(2-)的混凝土孔溶液中的腐蚀电位和极化电阻均更低,更易发生腐蚀;SO_(4)^(2-)对OH^(-)与铁表面反应的抑制作用略强于Cl^(-);SO_(4)^(2-)既可促使CaOH^(+)中Ca—OH键伸长,又可阻碍CaOH^(+)中OH基团与表面Fe原子间的作用,其对CaOH^(+)与铁表面反应的抑制作用明显强于Cl^(-).To reveal the difference of corrosion mechanism of steel bars in concrete under Cl^(-) and SO_(4)^(2-)action,and provide the theoretical basis for the control of concrete corrosion resistance under chloride and sulphate attack,the electrochemical behavior of reinforcement subjected to CI and SO_(4)^(2-)in concrete pore solutions was investigated,and the competitive adsorptions of corrosive ions(Cl^(-),SO_(4)^(2-))and passive ions(CaOH^(+),OH)on the Fe(100)surface were analyzed by the density functional theory based on the first-principles.The results show that the corrosion potential and polarization resistance of steel reinforcement in concrete pore solution with SO_(4)^(2-)both are lower than those in concrete pore solution with CI,indicating that the steel reinforcement corrosion occurs more easily in concrete pore solution with SO_(4)^(2-).The inhibition effect of SO_(4)^(2-)on the reaction of OH and iron surface is slightly stronger than that of Cl^(-) .Moreover,SO_(4)^(2-)can promote the elongation of Ca-OH bond,and block the interaction of the OH group in CaOHt and surface Fe atom,showing that the inhibition effect of SO_(4)^(2-) on the reaction of CaOH and iron is stronger than that of Cl^(-) .The results reveal the corrosion mechanism of steel reinforcement under the attack of CI and SO_(4)^(2-)in concrete.

关 键 词：氯离子 硫酸根离子 混凝土 钢筋 腐蚀机理 第一性原理 

分 类 号：TU528[建筑科学—建筑技术科学]