Revisiting the Effect of the Corrosion Potential, the Matrix Resistivity and the Oxygen Availability on the Corrosion Rate of Steel Bars Embedded in Mortar

Abstract

The parameters that control the corrosion process of steel bars embedded in concrete are the corrosion potential, the electrical resistivity and the oxygen availability. The objective of this work was to establish correlations between the corrosion rate and the mentioned parameters, to determine if the measurement of one of them, allows the estimation of the corrosion rate of the reinforcements. The parameters were measured in mortar specimens containing carbon steel and stainless steel bars. They were prepared with non-chloride addition and with chloride additions, in order to promote active corrosion; and were exposed for 18 months to different environmental conditions. The electrochemical parameters related to the state of the system were measured in a periodic basis. The results show the existence of very complex relationships between the measured parameters. It is concluded that it is not possible to predict the corrosion rate based on the measurement of the mentioned parameters.