Evaluation of cathodic protection performance of carbon steel pipeline buried in soil: A review

Carbon steel is commonly used in the gas and liquid pipeline transportation due to its low price while it possesses machanical properties accepted in most industrial applications. However, it has been reported to be susceptible to corrosion when exposed to various soil conditions. Cathodic protection (CP) is the most promising and already implemented technique for protecting buried carbon steel from corrosion. This study aims at reviewing the soil properties influencing the carbon steel corrosion process in the presence and absence of CP thus also giving the effectiveness of CP. The literature review carried out in this work has identified voltammetry as the only method for monitoring and estimating carbon steel residual corrosion rate under various soil conditions. The voltammetry was found to be a very reliable method that can be used to evaluate the CP effectiveness under soil conditions. However, more experimental tests have been proposed to extend the knowledge on all soil processes taking place during carbon steel corrosion in the presence of CP. Among other soil processes referred to for future studies are the soluble ionic species behavior in the soil which is linked to steel/soil vicinity pH, long-term exposure experiments as well as CP potential (insufficient, sufficient and overprotection potential).