Effect of moisture conditions and transfers on alkali silica reaction damaged structures

International audienceThe aim of this paper is to point out the water driving effect on the alkali silica reaction (ASR) expansion and particularly when modifications of moisture conditions occur After being submitted to a unidirectional moisture gradient during 14 months, the upper faces of ASR reactive beams were covered by water for 9 months This late water supply on the upper face rapidly produced large expansions, which mainly occurred along the transverse and the vertical directions resulting in large longitudinal cracks Companion nonreactive specimens were kept in the same environmental conditions in order to quantify the basic characteristics of moisture-dependent expansive behaviour of the material. The paper focuses on the effects of late water supply or late drying on already ASR-damaged concrete, which is a significant concern for reallife structures. Both structural effects of late water supply on ASR progress in already damaged structures and interpretation of such phenomena are described (C) 2010 Elsevier Ltd All rights reserve