The alkaliâ??silica reaction is a chemical phenomenon that, by inducing expansion and the\nformation of cracks in concrete, can have a severe impact on the safety and functioning of existing\nconcrete dams. Starting from a phenomenological two-phase isotropic damage model describing the\ndegradation of concrete, the effects of alkali-silica reaction in an existing concrete gravity dam are\nevaluated and compared with real monitoring data. Considering the real temperature and humidity\nvariations, the influence of both temperature and humidity are considered through two uncoupled\ndiffusion analyses: a heat diffusion analysis and a moisture diffusion analysis. The numerical analyses\nperformed with the two-phase damage model allow for prediction of the structural behaviour, both\nin terms of reaction extent and increase of crest displacements. The crest displacements are compared\nwith the real monitoring data, where reasonably good agreement is obtained.
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