Utilizing seawater and sea sand for construction engineering represents a significant approach to achieving efficient exploitation and utilization of marine resources. The incorporation of supplementary cementitious materials (SCMs) into seawater–sea sand cementitious materials can effectively improve their performance, provide a favorable service environment for steel reinforcement, and promote the sustainable development of these materials. This study examines the effects of several typical SCMs on the properties of seawater-sea sand mortars (SSSMs), including strength, hydration, microstructure, and chloride binding. The results show that the particle size and pozzolanic reactivity of SCMs are the primary factors influencing strength development. The unique solution environment created by seawater and sea sand significantly enhances the early hydration of SCMs and accelerates the formation of microstructure. The highly reactive Al 2 O 3 present in SCMs can interact with chloride provided by seawater and sea sand to form Friedel’s salt, thereby reducing the chloride content in SSSMs. The binding capacity of SCMs for free chlorides is influenced by both chemical binding and physical adsorption capabilities. The incorporation of GGBS, FA, and MK reduce the free chloride content in SSSC from 3.91 mg g −1 to 1.95–2.30 mg g −1 , 2.09–2.66 mg g −1 , and 0.92–1.70 mg g −1 , respectively. This study comprehensively compares the effects of several typical SCMs on the performance of SSSMs, and provides substantial experimental data to elucidate their influence mechanisms. These findings offer experimental validation for utilizing SCMs in seawater–sea sand cementitious systems.
Li et al. (Sat,) studied this question.