冻融循环下混凝土中氯离子传输机制细观模拟  

Mesoscopic Simulation of Chloride Ion Transport Mechanism in Concrete under Freeze-Thaw Cycles

作　　者：梁秋群 陈宣东 胡祥 LIANG Qiuqun;CHEN Xuandong;HU Xiang(College of Physics and Electronic Information Engineering,Guilin University of Technology,Guilin 541004,China;China Guangxi Key Laboratory of New Energy and Building Energy Saving,Guilin 541004,China;College of Civil and Architecture Engineering,Guilin University of Technology,Guilin 541004,China;Guangxi Engineering and Technology Center for Utilization of Industrial Waste Residue in Building Materials,Guilin 541004,China;Guangxi Beibu Gulf Engineering Research Center for Green Marine Materials,Guilin 541004,China)

机构地区：[1]桂林理工大学物理电子信息工程学院,桂林541004 [2]广西建筑新能源与节能重点实验室,桂林541004 [3]桂林理工大学土木工程学院,桂林541004 [4]广西工业废渣建材资源利用工程技术研究中心,桂林541004 [5]广西北部湾绿色海工材料工程研究中心,桂林541004

出　　处：《硅酸盐通报》2024年第6期2102-2110,共9页Bulletin of the Chinese Ceramic Society

基　　金：国家自然科学基金面上基金项目(12172121,U1934206);广西高校中青年科研基础能力提升项目(2023KY0269)。

摘　　要：基于经典应力水平-疲劳寿命方程,本文提出了以冻融循环次数为自变量的氯离子扩散系数数学表达式,并在此基础上建立了冻融循环下氯离子在混凝土中传输的三维细观数值模型,研究了冻融循环、混凝土细观结构特征、结合效应等因素对氯离子传输行为的影响。研究结果表明,冻融循环可以促进氯离子的扩散,当冻融循环的次数接近极限冻融循环次数时,这种促进作用十分显著。更重要的是,通过模拟混凝土细观结构中氯离子的扩散轨迹,揭示了界面过渡区促进氯离子扩散的机理。最后,通过对氯离子长期扩散性能模拟发现,在靠近侵蚀面区域出现了结合氯离子饱和区域,混凝土失去了对自由氯离子的固化能力,促进了氯离子扩散。Based on the classical stress level-fatigue life equation,a mathematical expression for chloride ion diffusion coefficient was proposed with the number of freeze-thaw cycles as independent variable.Furthermore,a three-dimensional mesoscopic numerical model of chloride ion transport in concrete under freeze-thaw cycles was established to investigate the effects of freeze-thaw cycles,mesoscopic structural characteristics of concrete,and bonding effects on chloride ion transport behavior.The results show that the freeze thaw cycle can promote chloride ion diffusion,and this promotion effect is significant when the number of freeze thaw cycles approaches the limit number of freeze thaw cycles.Furthermore,the mechanism of interfacial transition zone promoting chloride ion diffusion is revealed by simulating the diffusion trajectory of chloride ion in concrete meso-structure.Finally,through the simulation of the long-term diffusion performance of chloride ions,it is found that there is a saturated area of bound chloride ion near the ingress surface.And in the saturated area of bound chloride,the concrete loses the curing ability of free chloride and promotes chloride ion diffusion.

关 键 词：氯离子扩散 冻融循环 氯盐侵蚀 混凝土细观结构 界面过渡区 

分 类 号：TU375[建筑科学—结构工程]