Pitting corrosion analysis of steel rebars in concrete corrosive environment using COMSOL Multiphysics simulation

Abstract

Corrosion of reinforcement steels, induced by chloride ions penetrating into the concrete, is the main cause of early damage, loss of serviceability and safety of reinforced concrete structures, which can be even more severe. Among the different forms of corrosion pitting corrosion is an insidious localized form of corrosion. In this work, we have created a 3-D finite element model of reinforcement bar made of 316 stainless steel and plain carbon steel subjected to a corrosive concrete environment and investigated pitting corrosion behavior inside the rebars with the help of COMSOL Multiphysics software. In this work we have used two types of studies stationary and time dependent for the rebar material. The effect of pitting corrosion was investigated by examining the electrochemical parameters such as electrolyte potential and electrolyte current density and the variation in total electrode thickness change with time for both SS316L and plain carbon steel. The values of electrolyte potential distribution and electrolyte current density for plain carbon steel are higher than that of SS316L rebar. For 144h in case of plain carbon steel the value is -3.59î10ˉၪ µm while for SS316L it is -1.08î10ˉၮ µm. Total electrode thickness change increases as the time passes. Hence plain carbon steel is more susceptible to corrosion than SS316L which is more corrosive resistant material for rebars.