Abstract: “This paper investigates the effectiveness of micronized calcite in reducing expansion of concrete due to alkali-silica reaction. Three aggregates; two natural sands and one crushed stone aggregate were used preparing mortar bars in accordance with accelerated mortar bar test method, ASTM C1260. Performance of micronized calcite is determined by examining the expansions due to alkali silica reaction. Micronized calcite added to the mixtures at %10 and %20 replacement levels by weight of cement. Also in this research, effect of different cement usage to expansions was investigated by using the same method. Four different cements were used for this purpose. Usage of micronized calcite at %20 replacement level of cement was effective in mitigating ASR expansions whereas using it at %10 was not enough to suppress them. Different cement usage showed a minor difference between the expansions; however, the final decision about the reactivity of aggregate was indecisive.”

Keywords: Alkali silica reaction, Micronized calcite, Durability.