硫酸盐浓度对混凝土氯离子传输的影响研究  

Effect of sulfate concentration on chloride ion transport in concrete

作　　者：赖春祥 於德美 付腾飞 吴志鸿 张峰 LAI Chunxiang

机构地区：[1]福建农林大学,福建福州350108 [2]中建海峡建设发展有限公司,福建福州350015

出　　处：《福建建设科技》2020年第6期52-55,共4页Fujian Construction Science & Technology

基　　金：福建省自然科学基金(2019J05051);福建省教育厅中青年项目(KLA18050A)。

摘　　要：为了研究复盐侵蚀引起的混凝土结构性能与耐久性能劣化问题,采用硫酸钠与氯化钠复合盐溶液浸泡混凝土,按不同侵蚀龄期定期测定混凝土内部不同深度自由氯离子浓度,通过菲克第二定律解析解方程对测得的不同深度氯离子浓度进行拟合,分析硫酸根离子的存在及其浓度对混凝土表观表面氯离子浓度Cs和表观扩散系数Dapp时变规律的影响。通过指数型模型对表观表面氯离子浓度进行拟合,得到硫酸盐浓度、表观表面氯离子浓度Cs以及累积速率b之间数值关系。引入影响效应系数K,表征短期腐蚀下硫酸盐浓度对混凝土抗氯离子渗透性的影响。结果表明,同一深度混凝土自由氯离子浓度受硫酸盐浓度影响显著,硫酸盐浓度越高,表面氯离子浓度Cs、系数Dapp和K越小,混凝土抗氯盐侵蚀能力增加。Chloride ion concentration at different depths was monitored on concrete samples immersed in complex salts solution to study the deterioration of concrete structure performance and durability caused by double salt erosion,.The Fick second law analytic solution equation was used in curve-fitting.And the effect of sulfate concentration on the apparent surface chloride concentration Cs and apparent diffusion coefficient Dapp varied with time were analyzed.Exponential model was used to fit the surface chloride concentration and analyze the effect of sulfate concentration on Cs and accumulation rate b.The effect of sulfate concentration on the permeability of concrete was analyzed by introducing the effect coefficient K of sulfate in short-term immersion.The results showed that the higher the sulfate concentration,the lower the concentration of free chloride ion in the same depth of concrete,the slower the accumulation rate of chloride ion concentration on the surface,the longer the surface chloride concentration is needed to achieve stability,and the ability of concrete resisting to chloride attack was increased.

关 键 词：混凝土 表面氯离子浓度 表观扩散系数 累积速率 影响系数K 

分 类 号：TU5[建筑科学—建筑技术科学]