Multi-ion kinetics in pseudo-concrete electrolyte associated with macro-cell corrosion

Abstract

Steel corrosion is one of the damaging factors for structural concrete and has drawn engineering interest in the past decades. Macro-cell corrosion, a type of steel corrosion, is related to not only electric fields but also chemical substances of both polarized metals and electrolytes such as the concrete matrix. To investigate such multi-ion kinetics induced by macro-cell circuits, this study presents an experimental validation to build a numerical simulation platform using pseudo-concrete with which the species’ chemo-electrical profiles are dynamically measured with elapsed time to obtain evidence for broad-band verification and validation. As a key species of cementing material, the authors focus on the profiles of Ca2+ concentrations as a major cation of concrete around the positive and negative electrodes, which are significantly affected by the initial saturation of calcium hydroxide and the supply of carbon dioxide. Experiments and numerical simulation applied to concrete show satisfactory correlation to reveal the governing mechanism based on polarization and the Nernst-Plank theory with multi-ion mass equation.