Gao Shuling, Liu Leyu
School of Civil and Transportation Engineering, Hebei University of Technology, Tianjin 300401, China.
Civil Engineering Technology Research Center of Hebei Province, Tianjin 300401, China.
Materials (Basel). 2024 Apr 17;17(8):1843. doi: 10.3390/ma17081843.
Ultra-high performance concrete (UHPC) with excellent durability has broad application prospects in improving the durability of reinforced concrete (RC) structures. To clarify the influence of freeze-thaw cycles on the axial compression performance of UHPC-RC composite columns, axial compression tests were carried out on composite columns with different cycles (0, 100, 200, 300 cycles) and stirrup spacing (35, 70, 105 mm). The results showed that the UHPC shell did not fall off when the composite column was destroyed, even in the freeze-thaw environment. Under the action of freeze-thaw cycles, the peak load Nu,t and initial elastic modulus E of the composite column decreased, but the ductility coefficient μ increased. Increasing the stirrup spacing could significantly improve the ductility of the composite column. After 100 freeze-thaw cycles, the ductility coefficient μ of the 35 mm stirrup spacing specimen was 112.6% higher than that of the 105 mm specimen. A prediction model for the bearing capacity of UHPC-RC composite columns under freeze-thaw cycles was established, and the predicted results were in good agreement with the experimental results. This study lays a theoretical and experimental foundation for the application and design of UHPC-RC composite columns in the freeze-thaw environment.
耐久性优异的超高性能混凝土（UHPC）在提高钢筋混凝土（RC）结构耐久性方面具有广阔的应用前景。为阐明冻融循环对UHPC-RC组合柱轴心受压性能的影响，对不同循环次数（0、100、200、300次）和箍筋间距（35、70、105mm）的组合柱进行了轴心受压试验。结果表明，即使在冻融环境下，组合柱破坏时UHPC外壳也未脱落。在冻融循环作用下，组合柱的峰值荷载Nu,t和初始弹性模量E降低，但延性系数μ增大。增大箍筋间距可显著提高组合柱的延性。经过100次冻融循环后，箍筋间距为35mm的试件的延性系数μ比箍筋间距为105mm的试件高112.6%。建立了冻融循环作用下UHPC-RC组合柱承载力的预测模型，预测结果与试验结果吻合良好。本研究为UHPC-RC组合柱在冻融环境中的应用与设计奠定了理论和试验基础。
