Tanner, Russell

Critical chloride threshold, CT values for initiation of reinforced steel corrosion m
mortar typical of Florida coastal bridge substructures were determined in laboratory tests.
Previous research has reported CT values that vary by more than an order-of-magnitude,
making design life estimation for structures difficult. On this basis, experiments on
piling type specimens focused on [Cl-] contamination in the splash zone and coupling of
this steel to a large surface area submerged anode. The lower portion of simulated piling
was immersed and the region above the waterline periodically sprayed with NaCI
solution. Corrosion potential with respect to height above the waterline was monitored.
A temporary depolarization method for determining as to whether or not corrosion had
initiated is proposed. Chloride distribution at the reinforcement-concrete interface was
determined in piling using energy dispersive x-ray analysis and related to height with
respect to the waterline. Chloride threshold was related to corrosion potential.