Engineers from Novosibirsk State Technical University (NSTU) and Novosibirsk State University of Architecture and Civil Engineering (Sibstrin) have developed a prototype device for monitoring the distribution of steel fibers in steel fiber reinforced concrete — a composite material used in the construction of protective structures for nuclear power plants. The new compact device operates on the principle of a metal detector and is capable of accurately determining the uniformity of fiber distribution inside concrete products, according to the NSTU press service.
Steel fiber reinforced concrete is concrete reinforced with short steel fibers with a diameter of 0.25 to 1.2 millimeters. This material serves as a durable and long-lasting alternative to classic reinforced concrete, making structures lighter and increasing their resistance to dynamic loads. It is used in the creation of permanent formwork and enclosing walls, including at nuclear power facilities, where it is especially important to maintain accuracy and uniformity of composition.
The main advantage of the new device is its compactness and high sensitivity. The device is capable of distinguishing thin steel fibers from massive metal elements, such as reinforcement or embedded parts. This allows not only to assess the quality of fiber distribution, but also to detect hidden metal elements in the structure.
The principle of operation is based on measuring the differential signal between coils that respond to changes in the magnetic field. The device is capable of inspecting products up to 40 millimeters thick and operates in two modes: comparative and absolute. In the first case, measurements are compared with reference samples, which is especially convenient for production quality control.
According to Arseniy Morozov, head of the technical experiment laboratory at NSTU, the development has undergone mathematical modeling and testing. In the future, the device can be adapted for mass production and used in the construction of facilities with increased requirements for strength and safety.
