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

Concrete prism tests (CPT) for alkali aggregate reaction (ASR) are considered as a relatively reliable method covering the limitations of various aggregate tests. However, CPT has two problems—alkali leaching and drying. As an aggregate test, the CPT is a valuable because the alkali threshold for expansion can be determined by comparison with existing damages. However, as a performance test, these unintended effects need to be prevented and, wrapping concrete prisms with wet cloth containing an alkaline solution with the same pH as that of pore solution of concrete named as “alkali wrapping (AW)-CPT” is proposed in this study. This avoids the movement of alkalis between the cloth and the prisms and makes the acceleration conditions are clear and stable. The analysis of the cloth used for AWCPT at various acceleration conditions indicates the presence of significant amount of silica leaching depending on the conditions and the mechanisms discussed.