Research on the Creep Characteristics of Thermal Insulation Shotcrete under the Action of Temperature and Humidity Circulation

In order to explore the creep characteristics of thermal insulation shotcrete under the action of temperature and humidity circulation, a series of uniaxial compression creep tests were carried out with different cycles of temperature and humidity and hierarchical loading conditions. The test results show that the axial creep deformation and creep strain of the thermal insulation shotcrete specimens increase with the increase of the number of drying and wetting cycles under normal temperature water bath condition. After 28 cycles, the deformation value becomes larger obviously, and the creep strain increases greatly in the precycle period. The thermal insulation shotcrete axial steady-state creep rate increases nonlinearly with the increase of the number of drying and wetting cycles under different stress levels. When the number of adjacent cycles is 0–3, the average increase is larger, and the axial steady-state creep rate of thermal insulation shotcrete for 28 cycles increases with the increase of water bath temperature. The instantaneous deformation modulus of thermal insulation shotcrete decreases logarithmically with the increase of the number of drying and wetting cycles, and the total deterioration degree of the average instantaneous deformation modulus increases gradually, but the deterioration degree between adjacent cycles decreases successively. The thermal insulation shotcrete specimens with 3 cycles of fracture were mainly stretched, and with the increase of the water bath temperature, the specimen was damaged by shear failure. When the water bath temperature is 40°C, the fracture degree of the specimen increases first and then decreases with the increase of the number of cycles.

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