Abstract
Most galvanized structures exposed to marine environments worldwide show evident signs of deterioration, particularly in tropical climates. This happens shortly after erection, especially with those exposed to erosive environments, given the high wind speeds in those areas. Rehabilitation has, therefore been, deemed necessary, with the best option being the use of coatings. To that effect, the results obtained from Red Iberoamericana PATINA (Anticorrosive Protection for Materials, Exposed to the Atmosphere) after 42 months,’ exposure to aggressive atmospheres, were used. These showed that naked galvanized steel, should not be used in these atmospheres, and should be coated with high-performance systems such as epoxic systems, especially those with micaceous oxide-based pigments and a polyurethane finish. Not only coating systems, from different companies, were evaluated, but also the way in which the surface is prepared.
On this occasion, a new station was set up at the Lake Maracaibo crossing (very aggressive atmosphere/corrosion rate of 52.92 μm/year for galvanized steel in the area hit by the prevailing winds >C5, according to ISO9223), where the coatings were tested by using structural pieces (sections with 36 months’ exposure). Apart from these coatings, others currently sold on the international market for applications like the ones mentioned above were also used. In all, thirteen triplicate coating systems from six different companies were evaluated (78 systems). Accelerated tests, were also carried out, in the laboratory (Climatic chamber/ PROHESION) and in a station located in the Center for Corrosion Studies, using the ISO 11474 Standard.
The different coating systems with the best behavior were selected after the evaluations —both from the in situ application point of view and their effectiveness in this very aggressive exposure environment.
