PERFORMANCE OF GALVANIZED REINFORCING BARS IN CONCRETE SUBMITTED TO HALF IMMERSION IN SEAWATER AND NATURAL WEATHERING

摘要

Infrastructure constructed at the coastline of the Gulf of Mexico and the mexican Caribbean region is exposed to frequent dry and immersion cycles, mainly due to hurricanes or tidal incursions during the winter. Cylindrical samples were submitted to immersion and dry periods under natural conditions. The immersion cycles consist of a month immersion in seawater and a dry period of two months under normal atmospheric marine condition (airborne salinity and natural weathering). The evolution of corrosion process was measured by means of the open circuit potential and the corrosion current density calculated by linear polarization resistance measurements. Zinc-coated bars performance in concrete of low water to cement ratios showed an effective protection against corrosion, longer than 421 days. However, in concrete of higher water to cement ratios zinc on reinforcing bars has a corrosion rate between 20 μm/y and 40 μm/y, which starts earlier, as the first 200 days of exposure.