Modelling the mechanical behaviour of concrete subjected to Alkali-Silica Reaction (ASR) under multi-axial stress

Abstract

Modelling the effect of stress on the expansion of concrete subjected to ASR is of major importance to understand the mechanisms of damaged structures. In this paper, an existing poromechanical modelling combining creep and anisotropic damage is confronted with two recent experimental programmes on ASR-expansion under multiaxial applied stresses and prestressing. Based on parameters evaluated previously, the model is able to faithfully reproduce the concrete expansion in the three directions with only three parameters calibrated on the stress-free ASR expansion. The model points out the impact of the volume of ASR products formed in the porosity connected to reactive sites and to the induced diffuse cracking. The modification of the ASR volumetric expansion for concrete under stress observed in some experimental programmes could be explained by this effect. The model is compatible with a large variety of experimental observations performed on the effect of stress on ASR expansion available in the literature.