The presence of Alkali-Silica Reaction in concrete structures and damaged caused under this reaction

Abstract

The concrete structures during the life exploitations are under the severe conditions. Inthis way the different behavior of structures will be basic on the conditions. In this paper wewill present one of the important parameter, Alkali-Silica Reaction, and the damage under thisparameter in concrete components and in concrete structures. In most concrete, aggregates aremore or less chemically inert. However, some aggregates react with the alkali hydroxides inconcrete, causing expansion and cracking over a period of many years. This alkali-aggregatereaction has two forms: alkali-silica reaction (ASR) and alkali-carbonate reaction (ACR). Thefailure to fallow precautions may result in progressive degradation, demanding expensiverepair and improvement of concrete construction to preserve the prescribed function.In this state-of-the-art report we will present the concept of ASR, factors involved inASR and the means that are available to control it. Although there is extensive knowledgeabout the mechanisms of the reaction, the components of the aggregate that can reactharmfully and precautions to be taken to avoid resulting distress, gaps still exist in commonknowledge for ASR. This is partly true with respect to the applicability of test methods toidentify the potential for reactivity, methods to repair affected concrete and, means to controlthe consequences of the reactions in existing structures.