Wang Hao, Lv Nao, Lu Ziyi, Wang Haibo, Zong Qi
School of Civil Engineering and Architecture, Anhui University of Science and Technology, Huainan, 232001, Anhui, China.
China Construction Sixth Bureau Eighth Construction Co., LTD, Hefei, 230041, Anhui, China.
Sci Rep. 2024 Sep 4;14(1):20566. doi: 10.1038/s41598-024-71292-8.
To investigate the effects of high temperature and carbon fiber-bar reinforcement on the dynamic mechanical properties of concrete materials, a muffle furnace was used to treat two kinds of specimens, plain and carbon fiber-bar reinforced concrete, at high temperatures of 25, 200, 400 and 600 °C. Impact compression tests were carried out on two specimens after high-temperature exposure using a Hopkinson pressure bar (SHPB) test setup combined with a high-speed camera device to observe the crack extension process of the specimens. The effects of high temperature and carbon fiber-bar reinforcement on the peak stress, energy dissipation density, crack propagation and fractal dimension of the concrete were analyzed. The results showed that the corresponding peak strengths of the plain concrete specimens at 25, 200, 400, and 600 °C were 88.37, 93.21, 68.85, and 54.90 MPa, respectively, and the peak strengths after the high-temperature exposure first increased slightly and then decreased rapidly. The mean peak strengths corresponding to the carbon fiber-bar reinforced concrete specimens after high-temperature action at 25, 200, 400, and 600 °C are 1.13, 1.13, 1.21, and 1.19 times that of plain concrete, respectively, and the mean crushing energy consumption densities are 1.27, 1.31, 1.73, and 1.59 times that of plain concrete, respectively. The addition of carbon fiber-bar reinforcement significantly enhanced the impact resistance and energy dissipation of the concrete structure, and the higher the temperature was, the more significant the increase. An increase in temperature increases the number of crack extensions and width, and the high tensile strength of the carbon fiber-bar reinforcement and the synergistic effect with the concrete material reduce the degree of crack extension in the specimen. The fractal dimension of the concrete ranged from 1.92 to 2.68, that of the carbon fiber-bar reinforced concrete specimens ranged from 1.61 to 2.42, and the mean values of the corresponding fractal dimensions of the plain concrete specimens after high-temperature effects at 25, 200, 400, and 600 °C were 1.19, 1.21, 1.10, and 1.11 times those of the fiber-reinforced concrete specimens, respectively. The incorporation of carbon fiber-bar reinforcement reduces the degree of rupture and fragmentation of concrete under impact loading and improves the safety and stability of concrete structures.
为研究高温和碳纤维筋增强对混凝土材料动态力学性能的影响，采用马弗炉对两种试件（素混凝土和碳纤维筋增强混凝土）在25、200、400和600℃的高温下进行处理。高温暴露后的两种试件使用霍普金森压杆（SHPB）试验装置结合高速摄像设备进行冲击压缩试验，以观察试件的裂纹扩展过程。分析了高温和碳纤维筋增强对混凝土峰值应力、能量耗散密度、裂纹扩展和分形维数的影响。结果表明，素混凝土试件在25、200、400和600℃时的相应峰值强度分别为88.37、93.21、68.85和54.90MPa，高温暴露后的峰值强度先略有增加，然后迅速下降。碳纤维筋增强混凝土试件在25、200、400和600℃高温作用后的平均峰值强度分别是素混凝土的1.13、1.13、1.21和1.19倍，平均破碎能耗密度分别是素混凝土的1.27、1.31、1.73和1.59倍。碳纤维筋增强的加入显著提高了混凝土结构的抗冲击性和能量耗散，温度越高，增加越显著。温度升高会增加裂纹扩展的数量和宽度，碳纤维筋的高抗拉强度以及与混凝土材料的协同效应降低了试件中裂纹扩展的程度。混凝土的分形维数在1.92至2.68之间，碳纤维筋增强混凝土试件的分形维数在1.61至2.42之间，素混凝土试件在25、200、400和600℃高温作用后的相应分形维数平均值分别是纤维增强混凝土试件的1.19、1.21、1.10和1.11倍。碳纤维筋增强的加入降低了冲击荷载作用下混凝土的破裂和破碎程度，提高了混凝土结构的安全性和稳定性。
