The relationship between the evolution characteristics of C(N)-A-S-H gels and the microstructure, material composition, and chloride ion (Cl⁻) solidification ability of alkaline-excited materials (AEM) was investigated. The evolutionary characteristics of C(N)-A-S-H gels were influenced by the substitution rate of aluminum, which transitioned from slow to fast and then back to slow. This evolution led to significant changes in pore size distribution and phase composition. Specifically, the average pore size of the gels decreased from 64 to 29 nm, and intermediate impurities within the gel system were progressively reduced. The evolution of C(N)-A-S-H gels resulted in a mesoporous pore size distribution in AEM, enhancing Cl⁻ adsorption. Upon completion of the evolution, the Cl⁻ solidification rate of AEM was 92.62 % higher than in the initial period. Furthermore, AEM solidified Cl⁻ through both physical adsorption and chemical solidification. Physical adsorption was attributed to the mesoporous structure of C(N)-A-S-H gels, whereas chemical solidification resulted from the reaction between the aluminum phase and its precursors with Cl⁻ in AEM. As the gel structure evolved, the chemical solidification capacity of AEM gradually diminished, whereas the physical adsorption capacity increased.