Cathodic Protection of Prestressed Concrete Pipe

Prestressed concrete pipe has the reinforcement either partly embedded in the concrete core or totally placed over the core under a cement mortar cover. Lines of the latter type are bonded at the steel joint rings to provide for electrical continuity. With the aid of insulating joints at junction points, adequate control of galvanic currents is ensured. The lines also have the advantage of being suitable for cathodic protection. From an analysis of the line constants it follows that higher drainage current densities are required for this kind of pipe than in bituminous coated systems. The feeding points must be spaced closer due to stronger attenuation. Nevertheless cathodic protection can be economically applied under corrosive conditions. A field example has been described; constructional details also are given and design methods numerically discussed. 5.2.1