Review article

The article presents the study results of high temperatures impact in conditions of fire on the change in the ultrasound propagation velocity in steel fiber reinforced concrete with high-strength cement-sand matrix and fiber of different strength values and types at different contents. It is demonstrated that in the temperature range from 20 to 1100 °С, the ultrasound propagation velocity in steel fiber concrete scarcely depends of the presence of fiber and is mainly determined by the change in the characteristics of the matrix under the temperature exposure. The influence of the type and content of fiber is manifested only at a temperature of 500-600 °C and is determined by the degree of anchoring of fiber in the matrix.