Xu Bo, Liu Yongjian
Department of Bridge Engineering, School of Highway, Chang'an University, Xi'an 710064, China.
Department of Civil Engineering, School of Civil Engineering, Ordos Institute of Technology, No. 1 Ordos Street, Ordos 017000, China.
Materials (Basel). 2022 Oct 17;15(20):7233. doi: 10.3390/ma15207233.
The shear bond performance between steel tube and concrete is the basis of a synergistic effect between two materials. When a concrete-filled steel tube structure is damaged by freeze and thaw cycles, the shear bond performance will deteriorate, which will inevitably affect the safety of the structure. In this paper, the effects of the numbers of freeze-thaw cycles, section type of steel tube, and concrete strength on the failure mode, bond strength, and peak slip of concrete-filled steel tube are investigated. In addition, the load-slip curve, the shear bond strength calculation formula, and the peak slip calculation formula are obtained. The results show that the shear bond performance decreases with the increase in freeze and thaw cycles; after 20 freeze and thaw cycles, the shear bond strength of the round steel tube specimen with 30 MPa decreases by 33.33%, while that of peak slip increases by 11.49%; the shear bond strength increases with the increase in concrete strength, while the degree of decrease in shear bond strength after freeze-thaw cycles is reduced; the shear bond strength of the round steel tube push-out specimen is higher than that of square steel tube push-out specimen, and after 20 freeze and thaw cycles, the shear bond strength of the round steel tube push-out specimen with 30 MPa/45 MPa is 0.86 MPa/1.62 MPa, while that of square steel tube push-out specimen with 30 MPa/45 MPa is 0.40 MPa/0.50 MPa.
钢管与混凝土之间的抗剪粘结性能是两种材料协同作用的基础。当钢管混凝土结构受到冻融循环破坏时，其抗剪粘结性能会恶化，这将不可避免地影响结构的安全性。本文研究了冻融循环次数、钢管截面形式和混凝土强度对钢管混凝土破坏模式、粘结强度和峰值滑移的影响。此外，还得到了荷载-滑移曲线、抗剪粘结强度计算公式和峰值滑移计算公式。结果表明，抗剪粘结性能随冻融循环次数的增加而降低；经过20次冻融循环后，强度等级为30MPa的圆钢管试件的抗剪粘结强度降低了33.33%，而峰值滑移增加了11.49%；抗剪粘结强度随混凝土强度的增加而提高，冻融循环后抗剪粘结强度的降低程度减小；圆钢管推出试件的抗剪粘结强度高于方钢管推出试件，经过20次冻融循环后，强度等级为30MPa/45MPa的圆钢管推出试件的抗剪粘结强度为0.86MPa/1.62MPa，而强度等级为30MPa/45MPa的方钢管推出试件的抗剪粘结强度为0.40MPa/0.50MPa。
