Evaluating the efficacy of ground reactive aggregate in mitigating expansion due to alkali-silica reaction

This study presents an investigation into the potential use of finely crushed reactive aggregates to reduce expansion due to alkali–silica reaction (ASR). The powders, produced from different reactive rocks, were used as partial replacements of fine aggregate to evaluate their efficacy without altering the Portland cement, alkali, or calcium hydroxide levels in the mix. The powders were evaluated as potential mitigators for both highly and moderately reactive coarse aggregates. The experimental results demonstrated that although some aggregate powders can reduce ASR, their effectiveness is strongly influenced by aggregate mineralogy, powder fineness, and crushing method. Of the three rocks tested in this study, two showed efficacy in reducing ASR-induced expansion when crushed to sizes finer than 45 µm, whereas the third rock's powders did not. These findings suggest that aggregate powders may be a sustainable option for reducing ASR, provided that their mineral composition and fineness are carefully considered. • Powders produced from reactive aggregate can reduce ASR expansion. • The efficacy of a powder depends on rock type, crushing method, and powder fineness. • Powders containing argillite or microcrystalline quartz reduced ASR expansion. • For the same mineralogical composition, finer powders are more effective