The alkali-silica reaction is a universally known destructive mechanism in concrete that can lead to the premature loss of serviceability in affected structures. Quite an enormous number of research studies have been carried out focusing on the mechanisms involved as well as the mitigation and prevention of the reaction. A few in-depth discussions on the role of moisture and temperature exist in the literature. Nevertheless, moisture and temperature have been confirmed to play a vital role in the reaction. However, critical assessments of their influence on ASR-induced damage are limited. The available moisture in concrete needed to initiate and sustain the reaction has been predominantly quantified with the relative humidity as a result of difficulties in the use of other media, like the degree of capillary saturation, which is more scientific. This paper discussed the current state of understanding of moisture measurement in concrete, the role of moisture and temperature in the kinetics of the reaction, as well as the moisture threshold needed for the reaction. Furthermore, the influence of these exposure conditions on the internal damage caused by ASR-induced deterioration was discussed.
Keywords: alkali–silica reaction; damage rating index; moisture; relative humidity; relative humidity threshold; temperature.