Cathodic protection criteria for prestressed concrete pipe -- an update
- Ameron International Corp., South Gate, CA (United States). Engineering Development Center
Prestressed concrete cylinder pipe (PCCP) is used in water and waste water systems that serve virtually every major city in North America. Under certain conditions, such as high chloride environments, the steel can depassivate, leading to corrosion. Under these conditions, cathodic protection (CP) can be used to protect the encased steel elements. This paper provides the theoretical consideration and the results of laboratory and field investigations performed during the past decade to determine the effects of CP on the performance of passivated, corroded, and split prestressing wire immersed in an environment to simulate sound mortar and mortar surrounding severely corroded wire. The current densities required to achieve a 100 mV polarization or depolarization shift and the maximum potential criterion to prevent hydrogen embrittlement were determined. The effect of low pH due to corroding wire, the susceptibility of prestressing wire to hydrogen embrittlement, and the approximate length of time and potentials to produce hydrogen embrittlement and eventual wire failure were determined. The effect of discontinuing high levels of CP on the diffusion of hydrogen from wire and the recovery of ductility was evaluated. The amount of current flowing to the prestressing wire and steel cylinder at various current densities were also determined. Case histories of five cathodically protected pipelines are given. The data and results are presented and the minimum and maximum potential levels are recommended. The use of potential monitoring of PCCP to locate corrosion and possible causes of corrosion requiring CP is also presented.
- OSTI ID:
- 351774
- Report Number(s):
- CONF-980316-; TRN: IM9927%%299
- Resource Relation:
- Conference: Corrosion `98, San Diego, CA (United States), 22-27 Mar 1998; Other Information: PBD: 1998; Related Information: Is Part Of Corrosion `98: 53. annual conference and exposition, proceedings; PB: [6600] p.
- Country of Publication:
- United States
- Language:
- English
Similar Records
In search for criteria to avoid embrittlement on prestressed concrete pipe
Long-term effects of cathodic protection on prestressed concrete structures: Hydrogen embrittlement of prestressing steel