Quality control of monolithic concrete placement in a structure with a non-removable steel-fiber concrete formwork

Currently, permanent formwork made of high-strength steel fiber concrete (hereinafter SFB) is used in the construction of structures of nuclear power plants (hereinafter NPP). The use of reinforced formwork blocks with permanent formwork from SFB makes it possible to implement a precast-monolithic construction method, significantly increasing the speed of erection of blocks. At the same time, the use of this technology leads to problems of quality control of the laying of monolithic concrete, where it is hidden inside an armored block with permanent formwork. Experimental studies have been carried out to search for defects of various types and sizes inside the formwork block using the main methods of concrete flaw detection: through ultrasonic sounding, ultrasound tomography, radiography (georadar). Recommendations are given on ways to control the quality of monolithic concrete placement. It has been established that the most suitable method of control is ultrasound tomography, which allows to identify a defect behind a permanent steel-reinforced concrete formwork.