Optimisation of sacrificial anode cathodic protection system in chloride-contaminated reinforced concrete structure

For chloride-contaminated reinforced concrete (RC) structures, sacrificial anode cathodic protection (SACP) is an effective method to control steel corrosion. However, some adverse phenomenon, such as insufficient protection current or excessive anode consumption, might affect system operation. The motivation of this work is to optimize SACP systems by generating optimal tradeoff between its efficacy and efficiency: 1) maximizing the steel corrosion current reduction; and 2) minimizing the anode mass consumption. In this study, five SACP systems in chloride-contaminated beam were simulated to investigate the influence of anode arrangement on the steel corrosion current reduction and anode consumption. The result reveals that halving the anode spacing has better improvement on corrosion current inhibition compared to doubling anode size. Simultaneously, it was found that corrosion current reduction was accompanied by significant increase in the cathodic current, and this increment of cathodic current leads to more than 50% additional anode consumption. Based on a comprehensive evaluation, in an SACP system, when the current supplied by anode corrosion is 5.0–7.5 times steel corrosion current, the SACP system efficacy and efficiency can be balanced. [Display omitted] •SACP system may not reach the expectation due to inappropriate system arrangement.•Anode spacing but not mass has significant influence on steel corrosion inhibition.•Only less than 30% anode consumption is used to control steel corrosion.•Increasing SACP system efficacy is accompanied by decreasing efficiency.