Potential distribution within a cathodic protected steel reinforced cocrete structure

الملخص EN

Impressed current cathodic protection system was installed for a reinforced concrete structure which consists of two slabs (50 cmx25cmx10 cm) dimensions and connected by a concrete column in the middle [15cm x 15 cm cross section] and 100 cm long.

NaCl was added to the concrete mix (1% Cl based on cement weight) in order to simulate chloride induced corrosion of the steel reinforcement.

Steel tendons in form of a grid were used and were inserted over one of the slabs from the top and with 5 cm distance away from the reinforcement.

Potential of the reinforcement was measured after 28 days of curing and was found to be –433 mV vs.

CSE.

Within the whole structure, steel reinforcement was polarized by means of a dc-current source.

Polarization was done in such a way to adjust the IR free (instant off) potential of the reinforcement next to the anode to be –850 mV according to CSE.

Protection potential readings were measured along the structure by a copper-copper sulfate electrode and according to ASTM C876.

Mapping of polarization potential was done throughout the whole structure.

It was found that the potential of the reinforcement next to the anode achieved the potential requirements for protection while the polarization potential decreased to values below the open-circuit potential along the structure away from the position of the anode.