阳离子对C-S-H凝胶孔内氯离子扩散影响的分子模拟  

Molecular Simulation of Chloride Ion Diffusion Performance in C-S-H Pores under Influence of Different Cations

作　　者：李冬[1] 桑文龙 吴洁琼 金浏[1] LI Dong;SANG Wenlong;WU Jieqiong;JIN Liu(Key Laboratory of Urban Security and Disaster Engineering of China Ministry of Education,Beijing University of Technology,Beijing 100124,China)

机构地区：[1]北京工业大学城市与工程安全减灾教育部重点实验室,北京100124

出　　处：《建筑材料学报》2025年第1期1-8,共8页Journal of Building Materials

基　　金：北京市科技新星计划(20220484047);国家自然科学基金青年项目(52108106)。

摘　　要：基于分子动力学方法,探究了4种阳离子(K^(+)、Na^(+)、Ca^(2+)、Mg^(2+))对氯离子在水化硅酸钙(C‑S‑H)凝胶孔中扩散行为的影响机理.结果表明:C‑S‑H对氯离子的吸附量与其对阳离子的吸附能力相关;Ca^(2+)和Mg^(2+)可以促进氯离子的吸附,使C‑S‑H中的表面钙容易脱附进入溶液,延长氯离子和孔隙水的空间相关性,导致氯离子周围形成多层水合壳,降低其扩散能力;在被C‑S‑H层吸引的阳离子以及水分子的共同作用下,4种溶液中C‑S‑H凝胶孔中的氯离子扩散系数大小依次为KCl>NaCl>CaCl_(2)>MgCl_(2).Based on the molecular dynamics simulation,the effects of four cations(K^(+),Na^(+),Ca^(2+),Mg^(2+))on the diffusion behavior of chloride ions in the calcium silicate hydrate(C‑S‑H)pores were investigated.It is found that adsorption capacity of C‑S‑H for chloride ions is related to its adsorption capacity for cations.Ca^(2+)and Mg^(2+)can promote the adsorption of chloride ions,and the desorption of surface calcium in C‑S‑H can be easily facilitated into the solution,in which the spatial correlation between chloride ions and pore water is prolonged,resulting in the presence of multiple layers of hydration shells around chloride ions and the reduction of the diffusion ability.Under the combined actions of cations attracted by the C‑S‑H layer and water molecules,the ranking of diffusion coefficients of chloride ions in C‑S‑H pores in four solutions is KCl>NaCl>CaCl_(2)>MgCl_(2).

关 键 词：分子动力学 水化硅酸钙 氯离子扩散 阳离子 吸附能力 

分 类 号：TU528.01[建筑科学—建筑技术科学]