Prestressed concrete cylinder pipe (PCCP) used in two pipelines for the Tarrant County Water Control and Improvement District Number One system has experienced corrosion failure within the first ten years of service. Mechanical damage to the mortar coating during installation and/or waterhammer pressures, due to weather-related power failures which raise line pressure above the elastic strain limit of the outer mortar coating, result in cracking of the coating and develop a migration path for chlorides in the soil to reach the prestress wire. A safe, reliable cathodic protection system is required to keep the lines viable for their design life. A sacrificial zinc anode cathodic protection system was installed, both to prevent corrosion and to minimize embrittlement damage to the prestress wires. Total cost for the retrofit cathodic protection system is about four percent of the cost of the initial construction of the two lines. It is anticipated that the cathodic protection system will extend the useful life of both pipelines for decades.
Keywords: calcareous exudate, cathodic protection, elastic strain limit, embrittlement, line surge, prestressed concrete cylinder pipe, strain aging, zinc sacrificial anodes.