Finite-element modelling of alkali–aggregate reaction in a concrete hydraulic structure

Alkali–aggregate reaction (AAR) in concrete has been found to cause serious concerns for the operation and integrity of many mass and reinforced concrete structures, hydraulic structures (dams, powerhouses, etc.) and any other concrete structure that is exposed to moisture. It is known that the kinetics of AAR is strongly driven by temperature and moisture, among other parameters, and the induced strain is assumed to be oriented according to the stress state. Due to complexity of the AAR and its multi-physical nature, the use of chemomechanical modelling is very helpful for making predictions in terms of displacements and concrete damage. Moreover, macro-modelling approaches are frequently preferred for engineering work in real structures. In this context, this paper presents the implementation of a chemomechanical model of AAR for concrete using Abaqus/Explicit modelling software. With this approach, the effects of AAR are introduced by way of the Vuexpan user subroutine jointly with the concrete damage plasticity model of Abaqus. Verification of the proposed model was carried out at the material level. Moreover, a case study of a real hydraulic structure affected by AAR located in North America is presented.