Steel corrosion is the most frequent cause of early deterioration and shortening of service life of reinforced concrete structures. Huge costs and safety issues related to steel corrosion in concrete resulted in development of a wide range of technologies and materials in order to increase the durability of reinforced concrete structures. One of the methods, which delay or fully prevent corrosion, is the use of certain types of corrosion resistant steel with lower alloying elements, which are more corrosion resistant than carbon steel, while their price is significantly lower than stainless steel. The aim of this thesis was to analyse the corrosion process on reinforced concrete columns that were exposed for 10 years to the real marine environment below the Krk bridge. The columns were reinforced with different types of steel, and each column consisted of 2 carbon rebars and 2 corrosion-resistant rebars. Tests were carried out on total of five types of reinforcing steel: carbon steel (B500B), ferritic steel (TOP12), austenitic steel with higher nickel content (304L), austenitic steel with lower nickel content (204 Cu), and two types of duplex steel (1.4362, 2205). The corrosion process was analyzed on a particular type of steel with the aim of investigating the influence of the type of alloy on the long-term behavior of steel in the marine environment. It was also necessary to establish the influence of stainless steel reinforcement on the corrosion rate of ordinary carbon steel reinforcement, when it is placed inside the same concrete column. The research in this work was carried out with the help of an optical 3D scanner, which enabled the automated analysis of corrosion attacks on different types of steel.