Article ID: MS-24-5
This study examines the potential of sulfuric acid treatment on naturally occurring mordenite to enhance its inhibitory effect on the alkali-silica reaction (ASR). Mordenite was subjected to varying concentrations of sulfuric acid to convert its exchangeable cations to H+. The efficacy of this conversion and its impact on inhibiting the ASR were subsequently assessed. With increasing sulfuric acid concentration, the contents of exchangeable Na and K cations in the mordenite decreased. Notably, treatment with 9 M sulfuric acid successfully converted ∼64% of the exchangeable cations to H+, although at the cost of 16% loss of exchange sites. Structural characterization confirmed that the zeolite framework was preserved following two acid treatments. However, there was no increase in the ion exchange cation, and the sulfur content increased relative to that after a single treatment. To assess the inhibitory effect of the acid-treated mordenite on the ASR, accelerated expansion tests were conducted. Mortar specimens with drilled holes were filled with cementitious grout incorporating mordenite pre-treated with 9 M sulfuric acid. Compared to the control samples devoid of the treated mordenite, the expansion rate of the sample containing the acid-treated mordenite grout decreased significantly by 67%. This inhibitory effect outperformed that achieved with the previously developed Li-EDI zeolite, which decreased the expansion rate by 33%.
