pH-dependent performance of alkaline electrolyzed water concrete: A comprehensive analysis of strength, durability, and microstructural evolution

Abstract

Aiming to address the environmental burdens and CO₂ emission issues caused by high cement clinker content in concrete, this study proposes a new approach for cement reduction in concrete through high active alkaline electrolyzed water (AEW) technology. In this study, through systematic design of three pH-gradient AEW systems (9.0, 10.0, and 11.0), the influences of AEW with different pH values on the mechanical properties, durability, and microstructural characteristics of concrete were investigated. The results showed that three AEWs accelerated cement hydration, evidenced by 23-min and 11-min reductions in initial and final setting times compared to NTW. Microstructural analyses indicated accelerated formation of cement hydration products in AEW systems, attributed to enhanced ionic activity, though pH variations exhibited little differential effects. AEW concrete demonstrated superior early-stage mechanical properties (optimal at pH value of 10.0), the strengths of AEW group increased by 10 % at 3 days and 8.5 % at 28 days than control group, with decreased growth rate during later curing stages. A lower cumulative mercury intrusion in AEW specimens verified microstructural densification through additional hydration product formation. Although the performance changes between AEW concrete with different pH values are still not significant, the synergistic effects of AEW's ionic adsorption and OH⁻ cluster permeability were considered as critical mechanisms, collectively improve the mechanical strength, and durability of AEW concrete, which can leads to a reduction in cement clinker content and CO₂ emissions for AEW concrete. The findings can provide a scientific foundation for the engineering promotion and application of AEW-based low-carbon concrete.