关键词: 高温, 钢纤维混凝土, 力学特性, 声发射, 实时监测, 振铃计数率

Abstract: The uniaxial compression tests of the reference concrete and steel fiber reinforced concrete under the thermo-mechanical coupling were tested, the acoustic emission technology was used to monitor the concrete under the action of thermo-mechanical coupling. The results show that compared with the reference concrete at the same temperature, in mechanical properties, the compressive strength of steel fiber reinforced concrete with four temperature ranges from 20 ℃ to 600 ℃ increases by 12.07%, 4.15%, 11.25% and 3.24%, the residual strength increases by 2.67 MPa, 3.51 MPa, 0.98 MPa and 2.74 MPa, and the stress curve of steel fiber reinforced concrete has better ductility. In acoustic emission, compared with the same temperature of the reference concrete, the steel fiber reinforced concrete releases more energy during the process of compression. The acoustic emission signal has higher activity and intensity, and the signal is longer in dense bands, and the maximum ringing cumulative count is greater, the macroscopic mechanical properties of concrete and its acoustic emission response have a good corresponding relationship. The steel fiber can delay the deterioration and damage of concrete at high temperature in real time.

Key words: high temperature, steel fiber reinforced concrete, mechanical property, acoustic emission, real time monitoring, ring count rate