The effects of anode distance and corrosion activity on current distribution for ICCP systems

Abstract

One of the most effective techniques to mitigate corrosion of steel reinforcement in concrete is impressed current cathodic protection (ICCP). This technique has been widely used for several decades; however, there is limited research systematically studying the various factors affecting the distribution of cathodic current over the area of steel reinforcement. Understanding how current is distributed in an ICCP system is crucial for its design to ensure that all areas of steel are sufficiently protected, and overprotection of certain areas is avoided. In this study, the effect of distance of the anode from the steel and level of corrosion on current distribution is investigated by applying a potential sweep and measuring the steel potential and current for specimens with three layers of steel at different depths. The findings from this study revealed an inverse relationship between cathodic polarisation with steel distance from the anode and that higher levels of corrosion can cause a more non-uniform current distribution favouring the closest bar to the anode.

Influence of various parameters on the current distribution and protection degree of impressed current cathodic protection for reinforced concrete with TiMMO mesh anodes

“…The same effect was observed by Bhuiyan et al [13]. It was hypothesized that the anomaly in the current values could be explained by an initial macro-cell current between the reinforcement layers flowing through the ICCP system [13]. The large difference in the steel potential between the reinforcement layers after start-up could explain the formation of a macro-cell current.…”

“…The reinforcement layer at a distance of 130 mm or 230 mm from the anode receives a higher current density than the layer the closest to the anode for prism 1 (CEM I 1 m% Cl), prism 2 (0 m% Cl), prism 3 (2 m% Cl) and prism 6 (Ø 8 mm). The same effect was observed by Bhuiyan et al [13]. It was hypothesized that the anomaly in the current values could be explained by an initial macro-cell current between the reinforcement layers flowing through the ICCP system [13].…”

Cathodic protection of carbon steel using zinc and magnesium as sacrificial anodes in different conductivity solutions

“…The cathodic protection by the sacri cial anode includes the use of high negativity metal (the anode) which ensures potential of more negative than − 0.85 V (vs. Cu/CuSO4) of the structure. This technique is used in limited areas and close distances, as the sacri cial anode cannot produce protection currents over long distances, because the protection voltage decreases when the structure to be protected moves away from the sacri cial anode due to the resistance polarization [Bhuiyan et al, 2019, Wang et al, 2020. The distance at which the sacri cial anode is effective is dependent on the electrochemical properties of anode, the resistivity of the medium, the size of the anode, and chemicals present in the medium.…”

“…Figures5 and 6shows the trend of protection currents with time for Zn and Mg, respectively, for different anode to cathode distances. The protection current requirement is the amount of current needed to achieve full cathodic protection to the structural surface[Brondel, et al, 1994;Bhuiyan et al, 2019]. It can be noticed that the protection current decreases with time for all the distance.…”

Influence of corrosion rates on polarization and current distribution of ICCP in concrete

“…The presence of actively corroding steel in concrete has been shown to make the distribution of current during cathodic protection uneven, favouring bars closest to the anode, provided corrosion rates do not vary between the bars [1][2][3]. This distortion appears to increase with corrosion activity [5]. Current distribution can be further complicated in the presence of an active-passive couple [6,7].…”