The overall voltage calculated may not actually be active throughout the whole; due to varying elctric potentials. The voltage applied may exceed the limitts at certain zones and may be insufficient for active cathodic protection in some other for a detailed and large reinforcing cage. The heterogeneity may occur during operation as well due to elctrochemical changes taking place. My advice would be to divide the volüme to be protected into smaller zones and determine and apply the passivation voltages accordingly. Monitoring and adaptations during operation seem to be indispensable.

You are not doing wrong. You should be taking into account the variability of the system.

I should point out also the effect of heterogeneous polarization and masking effect which makes active cathodic protection practically a difficult method.

Dear Professor Guner, Thank you for your response. I understand that anode current distribution can be a factor when it comes to polarizing the complete area of steel reinforcement in cases of large setups. Due to the unequal current distribution, the polarization achieved at different regions will naturally be different. This effect is further compounded by the heterogeneity of the concrete (for example, different salt concentrations). However, my experiment is a very simple setup with a single reinforcing bar with a anode ribbon placed directly beneath the bar. I highly doubt that the current distribution is a major factor in my specific experimental setup. Is there any other possible reasons?

Hi Aria, Thank you for the references. They seem to be useful