Influence of Alkaline Electrolyzed Water on the Strength, Shrinkage Behavior, and Microstructure of Alkali-Activated Fly Ash/Slag Composites

In this study, the effects of highly active alkaline electrolyzed water (AEW) on the mechanical properties, shrinkage behavior, alkali activation reaction characteristics, and microstructure of alkali-activated fly ash/slag mortars at different alkali concentrations are systematically investigated, with ordinary tap water as the reference (OM group). The results showed that the EM group exhibited improved strength compared with the OM group. Specifically, the 28 d compressive and flexural strength of EM mortar at an alkali concentration of 4.0% were 13.5% and 7.5% higher than those of OM mortar, respectively. The 28 d drying shrinkage rate of the EM group was reduced by 7.3-11.2%. The EM group had a higher mass loss in the bounding water decomposition stage and a lower mass loss in the Ca(OH)₂ and CaCO₃ decomposition stages. XRD results showed that the EM group had a broader and stronger characteristic peak of N-A-S-H/C-A-S-H gel and a weaker characteristic peak of Ca(OH)₂ than the OM group. The enhancement mechanism of AEW was attributed to its high ion activity, the dense microstructure formed by sufficient alkali activation reaction reduced the pore content, thereby improving the strength. The AEW-based alkali-activated material in this study can be widely used in green low-carbon infrastructure fields such as new energy infrastructure and ocean engineering.