Finite element simulation of expansion and damage in RC elements affected by alkali‐aggregate reactions

Abstract

AbstractAlkali‐aggregate reaction (AAR) is a detrimental reaction between alkalis originating from cement and aggregates that contain reactive minerals. This reaction produces an expansive gel in hardened concrete that may cause internal stresses and cracking, after which it would be critical to evaluate the safety of the AAR‐affected structure. This paper presents a calculation framework primarily using the finite element method to simulate the structural behavior of reinforced concrete members affected by AAR. Numerical subroutines are used to calculate the anisotropic distribution of AAR‐induced expansions at each integration point, considering the stress field at each time step, whereas changes in the properties of concrete due to the progression of AAR are also considered. The modeling approach is successfully validated based on experimental data from several studies on AAR‐affected members that were reinforced in 1, 2, and 3 orthogonal directions in terms of load–deflection behavior and damage patterns. The mechanical properties of concrete were found to negligibly affect the distribution of AAR expansions. A better correlation was observed with experimental data if compressive and tensile strengths of concrete are assumed unchanged and only the modulus of elasticity of concrete is reduced as a function of AAR‐induced expansion.