UHPFRC for the rehabilitation and protection of concrete surfaces against hydroabrasion. Hydraulic structures made of reinforced concrete show damage as a result of hydroabrasion and alkali-silica reaction. This damage can be repaired efficiently using the novel ultra-high-performance, fiber reinforced cementitious composite material UHPFRC (also called UHPC). UHPFRC is applied in relatively thin layers to exposed concrete surfaces with the aim of permanently repairing the concrete damage typical of hydraulic structures and protecting the reinforced concrete. This means that hydraulic structures can be strengthened for a long, continued service life. In Switzerland, the UHPFRC technology has been used for 20 years primarily for the maintenance of bridges and buildings. First applications for the rehabilitation and protection of hydraulic structures were already carried out. In this article, the hydro-mechanical abrasion behavior of UHPFRC is first described by means of laboratory tests and compared with concrete. Two hydraulic structures, a river weir and the turbine house of a hydroelectric power plant, are then described with concrete surfaces that were rehabilitated and protected with a UHPFRC layer ten resp. two years ago. First findings are available as to how the UHPFRC protective layer has proven itself in the case of the river weir.