Role of Cathodic Protection on Physical Condition and Pipe Break Linkage

Abstract

Cathodic protection plays a crucial role in preventing the corrosion of cast and ductile iron pipes. However, less attention has been given to the long-term chemical reactions affecting crack growth and failures of pipes with cathodic protection. The present study, therefore, attempted to fill this gap by developing a model where cathodic protection is positioned as the moderating variable in the relationship between physical condition and pipe break frequency. Data from 426 pipes installed between 1955 and 1974 were obtained from a large-scale municipality in Ontario, Canada. The results showed a direct effect of physical condition on the pipe break frequency (β=0.78, p<0.01), demonstrating that as the physical condition worsens, the rate of pipe breakages increases. The findings further support the long-term moderating role of cathodic protection on physical condition and pipe breakage linkage (β=0.42, p<0.01), indicating a lower likelihood of failure for pipes with cathodic protection than their counterpart with similar physical conditions. The predictive model for the likelihood of failure, expressed as the expected number of breaks within 10 years, is then presented as a function of the pipe condition and the cathodic protection. The study’s findings emphasized the significance of implementing cathodic protection for pipes in both aggressive and nonaggressive environments.