Modeling chloride ingress in concrete with thermodynamically calculated chemical binding

Abstract

An alternative approach is developed to incorporate chloride binding/release processes during modeling of ingress of external chlorides in concrete through the use of thermodynamic modeling of chemical reactions. Transport of chloride in concrete is modeled through transient finite element analysis. At each time marching step, the chloride binding/release reactions are modeled using thermodynamic calculations. For this purpose, an open-source thermodynamic modeling software is used to model all possible reactions within the cementitious matrix including the reactions of chlorides with unhydrated and hydrated cementitious materials. The predictive ability of thermodynamic calculations is presented by comparing them with experimental data. The proposed and traditional modeling approaches for chloride transport with binding are compared. Finally, a parametric investigation is presented to demonstrate some of the strengths of the proposed approach using thermodynamic calculations over the traditional approach using binding isotherms to simulate chloride ingress in concrete.