Abstract
Presence of late-expansive aggregate in concrete has been recently recognized as one of the critical problems associated with alkali-silica reaction (ASR). It has been pointed out that accurate evaluation of ASR potential of late-expansive aggregate is impossible with the present Japanese Industrial Standards (JIS) test method. The problem of late-expansive aggregate has been known for long in overseas countries, and some practical methods have already been proposed. Meanwhile, few research has been made on such aggregate to date in Japan. This paper reports an examination made on cores taken from an existing concrete structure containing sea sand as fine aggregate.
The applicability of petrography method to the detection of late-expansive aggregate and the evaluation method for diagnosis from three different accelerated expansion tests were investigated. The results revealed that the structure has less potential for further expansion and that the Canadian method was the most appropriate for diagnosis in case of containing late-expansive aggregate.
