Orthotropic modelling of alkali-aggregate reaction in concrete structures: numerical simulations

Alkali-aggregate reaction (AAR) is difficult to model due to the random distribution of the reactive sites and the imperfect knowledge of these chemical reactions. A new approach, based on a probabilistic description of the main physical parameters of concrete and AAR, allows to simulate orthotropic swelling of concrete subjected to AAR. The concrete is modelled like a damageable material having elastic and inelastic strains. AAR is modelled by a global kinetics including temperature and humidity effects. The coupling between mechanics and AAR makes it possible to simulate tests carried out on concrete specimens. The results, obtained in terms of axial and transverse strains versus time, for various levels of axial loading, show a good agreement between experimental results and model response. A finite element implementation of the model is then applied to reinforced concrete beam subjected to different gradients of humidity on its height. The results are achieved in terms of damage fields, non-homogenous swelling and force-displacement curves. (C) 2002 Elsevier Science Ltd. All rights reserved.