Abstract
The article discusses a technological solution typical for the renovation of hydrotechnical structures. Factors posing a threat to the safety of such structures are presented through the example of the renovation of a barrage. The methodology and the general scope of diagnostic activities necessary for the development of the technical condition assessment were proposed. Exemplary test results and technological solutions for repairing the concrete surface, carried out in the underwater part of the hydrotechnical structure without the need to shut down the facility, are presented. The specificity, the validity of the selection of technology and the beneficial properties of self-compacting concrete laid under water are described.