The article is devoted to research in the field of determining the strength of hydraulic concrete by destructive and non-destructive testing methods. The most important indicators of hydraulic concrete are highlighted, the purpose of its use, methods of protecting structures and methods of quality control are determined. The main purpose of this type of concrete is its use in the construction and reconstruction of hydraulic structures. Heavy concrete containing M500 Portland cement, granite crushed stone, sand, surface-active wood chemical additive (LHD) and modifying additive KT troi-5 is studied in this paper. Two batches of this concrete were tested for compression when adding the KT-troy-5 modifier in the amount of 10% and 12% by weight of cement. The results of determining the strength of concrete by destructive and non-destructive testing methods at a reconstructed hydraulic structure are compared. The concrete class of structures according to the measurement results according to Russian standards corresponds to B60 (equivalent to C55/67 according to EN 206-1), which means that this concrete can be classified as super-strong concrete. The main strength gain occurred in the first 28 days from the moment of filling the structure. The data obtained during the study can be used for the use of concrete of this composition in the construction and reconstruction of hydraulic structures, as well as for the inspection and quality control of concrete.