Abstract: In the construction of marine engineering, raw materials such as sea sand and coral sand are rich in certain chloride salts. During the preparation process, chloride ion in raw materials enters the interior of reinforced concrete, causing internal erosion and leading to the failure of reinforced concrete structures. A large number of experiments show that the cement hydration products C-S-H gel and Friedel's salt play an important role in improving endogenous chloride ion binding capacity of cement-based materials and reducing the risk of rebar corrosion. The presence of cement minerals, admixtures and AFm-like phase materials affect the formation of C-S-H gel and Friedel's salt, which in turn changes the chloride ion binding capacity of cement-based materials. This article reviews the changes of C-S-H gel and Friedel's salt under the above influences, and then analyzes the endogenous chloride ion binding effect in cement concrete, which provides a reference for the use of chloride ion binding materials to solve the problem of chloride ion erosion in reinforced concrete.

Key words: chloride ion binding, C-S-H gel, Friedel's salt, cement mineral, mineral admixture, chemical admixture, hydrotalcite