Prediction of Alkali Reactivity Potential of Some Australian Aggregates and Correlation With Service Performance

Abstract

Aggregate is a major component of concrete and has an important influence on its durability. If premature deterioration of concrete due to alkali aggregate reaction (AAR) is to be avoided, considerable attention must be given to the determination of the susceptibility of the aggregate to alkali attack. There are several methods for determining the potential reactivity of aggregates that sometimes produce conflicting results, causing uncertainty in deciding on the nature of the aggregate. This paper reports the results of testing several Australian aggregates for alkali reactivity by different methods. To determine the potential reactivity of aggregates, an accelerated test method is recommended, for which the results of laboratory experiments agree with field performance of the aggregate. This test method is expected to predict the field performance of aggregates with unknown service records in adverse conditions. The effectiveness of a blended slag cement and two known fly ashes in reducing the expansion of concrete caused by AAR has also been examined.