Rebar Shape Time-Evolution During a Reinforced Concrete Corrosion Test: An Electrochemical Model

Abstract

An electrochemical model is presented to calculate the rebar shape time-evolution in reinforced mortar specimens during forced corrosion tests. This provides a more realistic description than the usually used geometric models. The current distribution along the rebar perimeter is calculated by using Finite Element Method (FEM) to solve Laplace equation. Then, Faraday's law is used to relate current distribution to rebar volume increase due to corrosion products creation. The shape of the rebar section is obtained as a function of corrosion time.

Cement mortar cracking under accelerated steel corrosion test: A mechanical and electrochemical model

“…An electrochemical model was previously developed [49] to obtain rebar shape evolution during the performed corrosion test. It is here outlined.…”

“…Here it is assumed that the formed oxides stay around the rebar creating a layer between the metal and the mortar. This layer is bulkier then the original metal, provoking a displacement of the mortar [49]. The resulting r ox ðθ; tÞ is used as input in the mechanical crack model described below.…”

“…The specific objective of the research reported here has been to develop a resort model able to provide approximate predictions of the evolution of the cracking process, in order to facilitate the design of the experiments of accelerated corrosion of reinforced cement mortar specimens (duration of the experiments and selection of the relevant experimental parameters like the anodic current density). An electrochemical model has been used for describing the evolution of the rebar shape due to the accumulation of corrosion products generated during the electrically accelerated corrosion test [49]. Subsequently, a mechanical model has been implemented based on the standard use of Ansys Software [50] and the eXtended Finite Element Model (XFEM) [51], reaching an acceptable prediction of the time to appearance of the crack on the surface and the evolution of the width of the crack over time using standard software, which could easily be implemented to perform modeling of other specimen configurations.…”