Experimental study of cathodic protection of concrete from a 30 year old bridge
Gjorv, O.E. (editor)
Sakai, K. (editor)
Banthia, N. (editor)
An experimental study of cathodic protection (CP) was carried out with a conductive primer anode applied to specimens from a concrete bridge. The bridge was demolished after 30 years of service due to severe delaminations and reinforcement corrosion. Four specimens of approximately 1 m2 each were made and characterised by steel potential, concrete resistivity and corrosion rate measurements, chloride analysis and microscopy. The resistivity was strongly influenced by humidity and temperature. Active corrosion was present, varying locally. CP current distribution was studied between two layers of reinforcement. The steel near the anode received about 60 % of the current, while the remote steel received 40 %. Lead and Activated Titanium reference electrodes were installed for potential and depolarisation measurements. The distribution of polarisation was influenced by the distance from the feeding point. In particular at low temperatures it was difficult to obtain sufficient depolarisation of the steel. Lead and Activated Titanium reference electrodes were found suitable for monitoring free corrosion potentials and effectiveness of CP.
Architecture and Building
To reference this document use:
Proceedings 2nd International Conference on Concrete under Severe Conditions, CONSEC '98, Tromso, Norway, 21-24 June (volume 2), 1199-1208