In this paper, studies were conducted in a concrete structure built twenty years ago,
approximately, which due to the aggressive atmosphere of exposure (Progreso Port in Mexico), led to
their deterioration during an early age. The latest repair (over 4 years ago) was conducted with a partial
replacement of concrete which contains different concentrations of inhibitors: 4% zinc oxide (ZnO), 4%
of calcium nitrite (Ca (NO2)2), and 4% of mixture (2% ZnO + 2% Ca (NO2)2), in addition to the repair
with conventional concrete. Electrochemical behavior of the repairs was done through the linear
polarization resistance technique (Rp) and the corrosion potential by a commercial corrosometer. After
over four years of exposure, ZnO is the only inhibitor that shows a clear passivation (Ecorr <-200 mV and
an icorr of <0.2 µA/cm2).
On the other hand, steel piles were evaluated over eight years exposure in a platform located in
Lake Maracaibo, Venezuela, lined with concrete in the wave and splash zone. ZnO was added to the
concrete in the range of 0.0-3% and the results indicate that only the concrete coating with 1% ZnO
performed very well with and without the cathodic protection system installed in the submerge zone.
Keywords: Reinforced concrete, inhibitors, zinc oxide, polarization resistance, coatings, repairs