Abstract. Actual problems of diagnosing the corrosion condition of hollow reinforced concrete structures are considered using reinforced concrete supports of the contact network as an example. Existing methods of diagnosing hollow reinforced concrete structures are discussed, advantages and disadvantages of these methods are revealed. The method of laser spectroscopy is reported to be the most promising approach to solving the problem due to its high reliability and the possibility to transmit laser radiation by fiber optic cable. A new design solution is proposed for positioning an optical probe inside a hollow structure to check the surface of the underground part of the reinforced concrete support. The optical probe is designed to determine the quantitative composition of corrosion products released to the surface of concrete by means of laser spectroscopy. A diagram of the optical sensor of the proposed device is presented, the sensor design is described. The proposed device allows to obtain quantitative information on the concentrations of corrosion products on the surface of reinforced concrete structure. Thus, by performing measurements on the surface and evaluating the condition of the reinforcement, it is possible to predict the residual strength of the supports, depending on the location of the point of greatest corrosion attack.

Keywords: reinforced concrete structure, corrosion, laser-induced breakdown spectrometry, positioning system, optical probe, fiber optic cable

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