To facilitate wider application of electrochemical chloride extraction in the rehabilitation of concrete bridges, this investigation was initiated with the objectives of improving the effectiveness of the treatment and contributing to the determination of additional service life that results from treating a structure. This interim report describes the progress made in ascertaining the cause of the abrupt drop in the amount of current that can pass through salt-contaminated concrete. This reduction in current, typically observed during the first several days of treatment, in turn relates to a decrease in chloride removal.