关键词: 冻融循环, 碳纤维布, 碳纤维, 混凝土, 相对动弹性模量, 能量耗散, 复合材料

Abstract: In order to investigate the effect of carbon fiber reinforcement on the frost resistance and energy dissipation of concrete materials, the longitudinal wave velocity and mechanical properties of four kinds of concrete (plain concrete, carbon fiber concrete, carbon fiber concrete, carbon fiber concrete and fiber fabric concrete) after freeze-thaw cycles (0, 25, 50, 75, 100 times) were obtained by using a longitudinal wave tachometer and an electro-hydraulic servo press. The effects of carbon fiber reinforcement method and number of freeze-thaw cycles on relative dynamic elastic modulus, peak stress, energy dissipation and damage degree were analyzed. The results show that: ① Compared with plain concrete with 0 freeze-thaw cycles, the relative dynamic elastic modulus of specimens with 25, 50, 75 and 100 freeze-thaw cycles decreased by 8.21%, 18.33%, 30.44% and 45.89%. The more freeze-thaw cycles occurred, the more significant the relative dynamic elastic modulus of specimens declined. Carbon fiber and carbon fiber cloth could both slow down the relative dynamic elastic modulus of specimens. ② As the number of freeze-thaw cycles increased, the peak stress of the four different concrete specimens showed a decreasing trend. Carbon fiber and carbon fiber cloth could not only enhance the strength of the specimens, but also enhance their freeze-resistance, and the combination of the two had the best lifting effect on the specimens. ③ Compared with the non-freeze-thaw specimens, the elastic deformation energy decreased by 3.87%, 7.63%, 9.67% and 12.70%, and the dissipative energy decreased by 10.42%, 21.97%, 30.16% and 41.60%, respectively, during freeze-thaw cycles of 25, 50, 75 and 100 times. The internal damage of the specimens was caused by freeze-thaw action, reducing the effect of sample energy storage and energy consumption. ④ The corresponding damage value of the three kinds of carbon fiber concrete at the peak stress is significantly higher than that of plain concrete, and the strengthening effect of carbon fiber can effectively improve the energy absorption effect, ductility and frost resistance of concrete materials.

Key words: freeze-thaw cycle, carbon fiber cloth, carbon fiber reinforcement, concrete, relative dynamic elastic modulus, energy dissipation, composites