Problems Relating Evaluation Methods for Alkari-reactivity of
Aggregate
-For Kyushu Standard Intended to Mitigate ASR-
By H. Matsushitam S. Tanaka and K. Yamada
Concrete Journal, Vol.43, No.10, Oct. 2005
- Synopsis
- In Japan, by the application of coutermeasures against alkali aggregate reaction, ASR, such as the restriction of total alkalis in concrete and the use of blended cement with the combination of evaluation methods of alkali reactivity of aggregate such as a chemmical method and a mortar-bar method, the majority of ASR has been controlled. However, some problems have remained in these methods when the wide variations of real aggregate, sever conditions for ASR, and increasing usage of alternative aggregates are considered. Besides, the foreign standards that are the basis of Japanese evaluation methods of aggregate are now charging. In this article, recent activities of RILEM TC191-ARP, reaction mechanisms of ASR, evaluation methods of aggregate including petrographic evaluation, and problems in these methods are outlined. Based on the information, "Kyushu Standard" in which the application of blended cement is recommended as a standard mitigating method from a realistic point of view is introduced and reasonable countermeasures against ASR are proposed.
- Keywords:
- alkali aggregate reaction, ASR, evaluation, coutermeasures, chemical method, mortar bar method, RILEM, Kyushu standard, blended cement, petrographic evaluation
