Alkali-Silica Reactivity of Lightweight Aggregates and Proposal of ASR Assessment
By A. Sugiyama and K. Torii
Concrete Journal, Vol.46, No.10, Oct. 2008
- Synopsis
- In order to investigate the possibility of occurrence of alkali silica reaction (ASR) in concrete containing lightweight aggregates, the alkali-silica reactivity of six artificial lightweight aggregates and one natural lightweight one, which are now produced in Japan, was comparatively examined according to the chemical method, JIS A 1145, and three types of mortar bar methods, JIS A 1146, ASTM C 1260 and Danish method, along with their mineralogical properties. From the results of ASR assessment test, it was found out that the alkali-silica reactivity of all lightweight aggregates was determined as "Not Innocuous" by the chemical method, JIS A 1145, but that it was determined as "Innocuous" by three types of mortar bar methods. Furthermore, although ASR gel was actually formed around the shell or in the voids of some lightweight aggregates in concrete, the expansion behavior of concrete bar was not so significant because the internal voids in lightweight aggregate may eliminate the expansion pressure due to ASR, Furthermore, the appropriate test procedure for ASR assessment of the concrete containing lightweight aggregates was discussed and proposed.
- Keywords:
- artificial lightweight aggregate, reactive component, alkali-silica reactivity, chemical method, accelerated mortar bar method, concrete bar method
