One of the major problems concerning cathodic protection (CP) of rebars in concrete structures, is the reliability of the system operation as continuously as possible. This solution has been applied in France in the following case. A cathodic protection system was designed and installed on the Noirmoutier Bridge (France), a reinforced concrete structure over a small pass on the Atlantic Ocean. The design and the installation of the system have met the requirements of the new French standard for cathodic protection of steel in atmospheric concrete. It means that the main effectiveness criterion is the rebar potential under cathodic protection. The initial protection current I was determined by using a Elog I polarization plot: using a Elog I polarization plot: this procedure makes it possible to check that the system had been correctly designed and to detect possible shorts in the electrical circuit. Then, after six month operation, the rebar potential was maintained at level a little lower than -850 mV CSE. As far as the monitoring is concerned, the Noirmoutier Bridge CP system is controlled by using; (1) remote data acquisition for measuring protection current, potential of rebars, temperature, etc; and (2) an adjustable power source, located in the field, which is connected to a microcomputer, located in a laboratory, through a phone line. (A)
Abstract