Vliv použití ochranných povlaků na životnost mostních konstrukcí z patinujících ocelí

Abstract

The bridge structures are now designed with possible repairs to the life of 100 years. The Investment costs for construction of bridges and repair costs of emergency conditions are very high in case of failure to do regular repairs and maintenance. So it is therefore to make an effort to find the right solution how to lower the costs. This reduction must not be at the expense of the quality of the design. One of the possibilities is to use low alloyed steels with higher resistance against corrosion called patina. Under the right atmospheric conditions it creates a stable surface oxide layer of material, called a patina. This layer causes slow degradation process of the material. In case that there is not a cyclical exposure to moisture and drying of the surface material, weathering steel from corrosion point of view behave like ordinary carbon steel and corrode at the same speed. If the stable oxidizing layer will be not created, a suitable surface treatment will be applied at the material - coating system. Coating systems are the most frequently used for surface finishing which is applied on the bridge constructions. Currently there is a big range of coat systems for this application which is recommended by the manufacturer. The important role in the life of the coating paint is a suitable pre-treatment before paint application. Dissertation thesis focuses on the study of the corrosion resistance of selected paint systems, including the weathering steel surface preparation before paint system´s application. Experimental work were focused on testing of paint systems for weathering steel, which were blasted on the degree of surface preparation of Sa 1, Sa 2 and Sa 2 ½ and brushed to the degree of surface preparation St 2. The results of the resistance of paint systems exposed in high corrosive environments and exposure to road salt solution provide valuable information for practices.