Testing of Discrete Titanium Anodes for Cathodic Protection of Reinforced Concrete

Testing of discrete titanium-based anodes was initiated at J.E. Bennett Consultants, Inc. (JEBC) in September 2006. The purpose of these tests was to investigate the operating characteristics of three types of discrete anodes installed in reinforced concrete blocks and to determine the relationship between acid formation/damage and operating current. The anodes tested were mixed metal oxide (MMO) catalyzed Stargard^TM and round configurations installed in two different types of grouts. Test blocks were operated indoors and were ponded to prevent over-drying on a cycle similar to the test procedure used in ASTM Standard Test Method G-109.

This paper summarizes appearance, resistance, and voltage data collected over 566 days of operation. Autopsies were conducted on anodes after 203, 404, and 566 days on line. The amounts of Anode Reaction Product (ARP) are presented in the paper, together with pictures. Results were either excellent or good, based on the condition of the grout surrounding the outside surfaces of the anodes. The amount of ARP observed for the anodes was roughly proportional to the operating current density. These test results provide significant information for the application of discrete anodes in the concrete rehabilitation industry.