Abstract: This paper conducts an experimental study on the mechanical properties of carbon fiber fabric-confined damaged concrete under axial loading. Three variables of concrete damage degree, the number of carbon fiber cloth layers and carbon fiber cloth winding angle were designed, and the influence laws of the three variables on the stress-strain curve, peak stress, energy dissipation effect and mechanical damage degree of carbon fiber cloth confined concrete were analyzed by the test results. The test results show that compared to undamaged specimens, the mean values of damage to plain concrete under 0.4σ_m(σ_m is the uniaxial compressive strength of undamaged concrete specimens), 0.5σ_m, 0.6σ_m, and 0.7σ_m stress amplitude damage are 7.24%, 14.86%, 25.31%, and 36.66%, respectively. There is a good exponential function positive correlation between the damage degree and the damage stress amplitude. The confining effect of carbon fiber cloth enhances the peak stress and ductility of the specimen. After 0.4σ_m damage stress, compared with the specimens without carbon fiber cloth, the increase of peak stress in the specimens with 1, 2 and 3 layers was 34.99%, 55.16% and 64.42%. There is a negative correlation between the number of layers of carbon fiber cloth and the peak stress as a function of exponential, and the excessive amount of fiber cloth makes the stress increase in the specimen no longer obvious. The increase of the winding angle of carbon fiber cloth reduces the dissipation energy per unit volume of the specimen linearly, and the increase of the winding angle reduces the bearing effect of the fiber cloth in the specimen under the load. The increase of the stress damage amplitude reduces the mechanical damage of the specimen, the increase of the number of layers of carbon fiber cloth increases the mechanical damage of the specimen, and the restraint and protection effect of the fiber cloth greatly enhances the energy dissipation effect of the specimen.

Key words: damage concrete, carbon fiber cloth, degree of damage, peak stress, energy dissipation density, mechanical damage degree, composite material