The effect of pumice and zeolite on alkali silica reaction

Alkali-silica reaction (ASR) is a chemical reaction that takes place among the cement used in the concrete or alkali hydroxides coming from external sources and aggregates in concrete containing reactive silica components. By time, in the presence of moisture the reaction products cause expansion in concrete. Some of the mineral types that may contain reactive forms of silica are opal, chalcedony, cristobalite. In the first stage of this study, the most suitable of the selected mineral admixture were determined. In order to reduce the harmful effects of ASR, in place of cement various proportions of pumice, perlite and zeolite were used as complementary materials and the reactivity of the combinations of aggregate and the resultant cementitious material was determined in accordance with ASTM C1260 Accelerated Mortar Bar Method. At the end of the tests, it was found that perlite was not as effective as pumice and zeolite in the process of reducing ASR expansion. For this reason, in the later stages of the study pumice and zeolite were used which reduce the harmful effects of the reaction and after a certain rate that may decrease the expansion values of the mortar samples below the expansion limit stated in the standard. In the last stage of the study, in order to reduce the harmful effects of ASR, the influence of mineral admixtures, pumice and zeolite, on the durability of concrete was investigated.