Resumen
Making a decision to perform an overhaul of a damaged reinforced concrete structure should be preceded by an analysis of the real durability of that structure after the repair in connection with the anticipated service life. One of the basic problems is the avoidance of further corrosion of concrete and steel after the repair, which depends on the degree of concrete contamination with harmful chemical factors. It is particularly important to determine the content of chloride and sulfate ions which cause corrosion. Concrete pH is equally significant because it conditions effective passivation of the reinforcement. The paper presents the basic issues related to the main chemical threats, including the main sources of their origin as well as their limit values. It emphasizes the importance of conducting the chemical tests of concrete, which should be treated as one of the methods of determining structure suitability for an overhaul, especially in the context of subsequent durability. This seems obvious to an experienced specialist, but in practice, such studies are often ignored. Those considerations are backed up with selected examples of reinforced concrete industrial structures exposed to aggressive chemicals during their operation. The text shows the correlation between their technical condition and chemical test results as well as the influence of those results on making decisions concerning effective overhauls.