Ex-situ replication of concrete pore solution: alkali-activated concrete

This study presents a reliable methodology for simulating the evolving pore chemistry of alkali activated materials. Using ex situ leaching, binder alkali profiles were established, and concrete specimens were characterized over one year under air and water exposures via porosity, ion chromatography, and pH analysis. The protocol captured critical temporal shifts: carbonation in an air cured, calcium activated AAC reduced the pH from 13.08 to 12.65, driving a ∼60% decrease in the required mass of alkaline salts for accurate replication. These findings demonstrate that slight pH drops mandate major chemical adjustments, exposing limitations of current standards that assume static environments. Furthermore, a three-way ANOVA confirmed that the precursor, activator mix, and curing conditions significantly influenced the final pore solution pH. This highlights the need for a dynamic modeling approach to accurately replicate pore chemistry. Ultimately, this dynamic framework provides a realistic, scalable approach for long term performance assessment.