Potential alkali reactivity of South Island concrete aggregates

摘要

Previously, ASR had been considered to present a low risk for South Island concrete. Its detection in two sets of extensively damaged bridge piles in 2006 required a re-examination of this belief. Therefore one of the research tasks was to evaluate the potential alkali reactivity of South Island aggregate sources. Laboratory tests showed that aggregates from Oreti beach and nearby alluvial deposits are potentially alkali reactive, but may react slower than fresh volcanic materials, and concrete temperatures may need to exceed 60℃ to produce significant concrete expansion.