Contribution to the Development of Analytical Models to Forecast Alkali-Aggregate Reaction (AAR) Kinetics and Induced Expansion

Abstract

Alkali-aggregate reaction (AAR) is one of the most harmful distress mechanisms affecting the durability and serviceability of concrete infrastructure worldwide. Currently, there is a need to forecast future behaviour of AAR-affected concrete, and thus analytical and numerical models have been developed over the years. Larive developed a model in 1998 that is able to describe the behaviour of concrete samples in the laboratory. This model has been widely accepted and used by AAR community, even to predict the behaviour of concrete structures in the field. Larive’s model is based upon three main parameters and although they are normally set according to the concrete type under analysis, these parameters do not have a clear physicochemical meaning to describe AAR-induced expansion and development. Furthermore, it is widely known that AAR is influenced by several measurable variables such as the type and reactivity degree of the aggregates, temperature, moisture, and alkali content; those are currently not accounted for in Larive’s equation. This work aims to incorporate the previously mentioned parameters to Larive’s equation so that AAR kinetics and final expansion might be precisely described in the lab and/or field. Results indicate that the proposed modified Larive’s equation can predict AAR kinetics and final expansion in the laboratory although some modifications seem still necessary to assess field structures.