Abstract
The performance of zinc anodes embedded in mortar activated with lithium chemicals was studied with polarization scans, laboratory test blocks, larger test slabs, and a demonstration field trial. Environments studied included an indoor setting at 55% and 80% relative humidity, an outdoor setting in northeast Ohio, and a parking garage in New York.; Tests indicated that best performance was achieved with zinc anodes activated predominantly with lithium nitrate (LiNO3), with some lithium bromide (LiBr) added to enhance performance. Current efficiencies for zinc consumption were measured ranging from 93.6% to 97.0% in this environment. Using this combination of activators, significant flow of protective current was recorded for up to 3½ years. Anodes installed on four outdoor test slabs averaged over 0.2 mA after 1187 days on line, and the NACE criterion of 100 mV of potential decay was achieved on most test points at that time. It was demonstrated in a field trial that properly activated anodes could deliver sufficient protection to prevent the “anode ring effect.”; Discrete anodes activated with combinations of LINO3 and LiBr have been demonstrated to effectively extend the service life of concrete patch repair.
