Simulated reinforced concrete substructure element (piling) specimens were fabricated, cured
for twelve months and exposed partially submerged in natural sea water. The specimens were
made of mortar with 20% Fly Ash and a low water to cement ratio, simulating a FDOT Type V
concrete. Exposure involved, first, intermittent spraying of the above waterline zone to simulate
splash and spray and, second, electrically connecting the embedded reinforcement to
submerged bare steel bars to affect a potential gradient from relatively negative in the
submerged zone to positive in the atmospheric as occurs in actual members. Three different
polarization levels were achieved by inserting resistors. On-potentials and 24 hrs
depolarization tests at various elevations were used to better understand the influence of these
polarizations on potential vs. elevation and how it affects time to activation. Chloride analysis
and visual inspection was performed on selected terminated specimens. The proposed
specimen geometry coupled to a submerged rebar provides a good alternative to investigate
chloride threshold on partially immersed substructures.
Keywords: cathodic polarization, chloride threshold, concrete, rebar, depolarization.