采用分子动力学研究了不同浓度NaCl溶液对水化硅酸钙（calcium silicate hydrate, C-S-H）和钢筋钝化膜（γ-FeOOH）（下文简称为C-S-H／γ-FeOOH）界面黏结性能的影响，从界面处离子演化、径向分布函数、粒子强度分布、相互作用能和力学性能等方面揭示了NaCl溶液浓度的影响机理。研究结果显示，随着NaCl溶液浓度升高，层间离子从C-S-H表面脱离扩散至层间溶液，Na⁺离子进入C-S-H层中，离子对溶液中Cl^-离子具有吸附作用，导致C-S-H表面出现和Cl^-的离子团。此外，由于γ-FeOOH表面羟基振荡，为Na⁺离子提供吸附点位，致使γ-FeOOH表面Na⁺离子增多。当NaCl溶液浓度升高时，Ca_h—O_s的径向分布函数（radial distribution function, RDF）峰值逐渐降低，Ca_h—O_w、Ca_h—Cl和Na—O_s的RDF峰值均逐渐升高，该结果与离子强度分布一致，其中O_s为C-S-H中硅链上的氧，O_w为层间溶液水中的氧。离子与水中O_w形成离子键，导致C-S-H表面Ca_h—O_s离子键减少。Ca_h—O_s离子键的强度和稳定性优于Ca_h—O_w，故随着NaCl溶液浓度的升高，C-S-H／γ-FeOOH界面相互作用能和峰值应力均呈下降趋势。

Molecular dynamics method is adopted to investigate the effect of different NaCl solutions concentrations on the bonding properties of the calcium silicate hydrate/γ-FeOOH(C-S-H/γ-FeOOH) interface. The effect mechanism of NaCl solution concentration is revealed from the interface ion evolution, radial distribution function, particle strength distribution, interaction energy and mechanical properties. The results show that as the concentration of NaCl solution increases, interlayer ions separate from the surface of C-S-H and diffuse to the interlayer solution, Na⁺ ions enter the C-S-H layer. ions adsorb Cl^- ions in the solution, resulting in the ion clusters of and Cl^- on the surface of C-S-H. In addition, the γ-FeOOH surface hydroxyl oscillation provides adsorption points for Na⁺ ions, resulting in the increase of Na⁺ ions on the γ-FeOOH surface. When the NaCl solution concentration increased, the RDF peak of Ca_h—O_s gradually decreased and the radial distribution function(RDF) peak of Ca_h—O_w, Ca_h—Cl, and Na—O_s gradually increases, consistent with the ionic strength distribution. Where, O_s is the oxygen on the silicon chain in C-S-H, and O_w is the oxygen in the interlayer solution water. ions form ionic bonds with O_w in water, leading to a reduction of Ca_h—O_s ionic bonds on the C-S-Hsurface. Since the strength and stability of Ca_h—O_s ionic bond are better than that of Ca_h—O_w, therefore, the C-S-H/γ-FeOOH interfacial interaction energy and peak stress both show a decreasing trend with the increase of NaCl solution concentration.