Epoxy resins are widely used as construction and repair materials. However, their bond with the concrete substrate under wet conditions is of concern as the loss of compatibility will lead to the failure of the bonded system. The reported study investigated the effect of surface moisture at the epoxy/cement interface using molecular dynamics (MD) simulation. The model of the interface was built using calcium silicate hydrate (C–S–H), as a hydrated cement substrate and diglycidyl ether of bisphenol-F (DGEBF) as an epoxy resin. Subsequently, different layers of water molecules were inserted into the model to represent varying moisture concentrations at the interface. The interfacial properties of the dry and wet models were evaluated in terms of adhesion, debonding, and energy ratios. In addition, the radial distribution function (RDF) was employed to deeply investigate the atomic interaction between the cement surface and epoxy. The results of the model indicated that the adhesion properties were adversely affected by the presence of moisture at the epoxy/cement interface. The degradation in the adhesion at moisture contents of 3% and 6% was 37.49% and 72.02%, respectively. Additionally, it was found that the detachment increased, as evident from the values of debonding, at higher moisture contents due to an increase in the adhesion between the C–S–H and water molecules where the latter form hydrogen bonds with the substrate. This work provides valuable molecular-level insights into the epoxy/cement bond that can be used to design new epoxy resins suited for cement and concrete applications.

环氧树脂被广泛用作建筑和维修材料。然而，它们在潮湿条件下与混凝土基材的粘合是值得关注的，因为失去相容性会导致粘合系统失效。报告的研究使用分子动力学 (MD) 模拟研究了环氧树脂/水泥界面处表面水分的影响。使用水合硅酸钙 (C-S-H) 作为水合水泥基材和双酚-F 二缩水甘油醚 (DGEBF) 作为环氧树脂建立界面模型。随后，将不同层的水分子插入模型中，以代表不同的水分浓度在界面。干式和湿式模型的界面特性根据粘附、脱粘和能量比进行评估。此外，径向分布函数（RDF）被用来深入研究原子之间的相互作用水泥表面和环氧树脂。模型的结果表明，在环氧树脂/水泥界面处存在水分会对粘合性能产生不利影响。水分含量为 3% 和 6% 时，附着力下降分别为 37.49% 和 72.02%。此外，从脱粘值可以看出，由于 C-S-H 和水分子之间的粘附增加，后者与基材形成氢键，因此在较高的水分含量下，分离增加了。这项工作为环氧树脂/水泥键提供了有价值的分子水平见解，可用于设计适用于水泥和混凝土应用的新型环氧树脂。