福島県環境創造センター
Fukushima Environmant Creation Center

In a concrete prism test (CPT), expansion is accelerated by increasing temperature and alkali contents. Alkali leaching and drying are two problems with the CPT. Strict evaluation of their effects independently has been difficult. Therefore, to solve these problems, concrete prisms are wrapped in cloth wetted with a solution of alkali having the same concentration as the pore solution in the concrete. In this study, various Japanese reactive aggregates such as andesite containing opal and/or cristobalite, chert containing chalcedony, and several types of slow expansive aggregate containing cryptocrystalline quartz are examined. The results indicate that, depending on the aggregate type, expansion and mass gain differed on the basis of temperature and alkali content variation. Some of the alkali–silica gel was lost from the prisms without causing expansion. A performance test result showed that accelerated test conditions of the CPT were modified depending on the reactivity of the aggregate.