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掺纳米二氧化硅和钢纤维的超高韧性水泥基材料(UHTCC)具有良好的力学和耐高温性能。为探究UHTCC与钢筋在高温后的协同工作性能,文中对配光圆钢筋和变形钢筋的UHTCC试件在经历不同高温后的表观形态及拉拔试验中的滑移和破坏现象进行观察研究。试验表明:随经历温度的升高,UHTCC与钢筋的粘结应力逐渐降低;光圆钢筋的极限粘结应力和相应的滑移量呈负相关,UHTCC高温后疏松多孔,塑性变形能力加强,导致钢筋大滑移量的产生;变形钢筋与UHTCC的粘结应力显著大于光圆钢筋,两者粘结应力随经历温度升高具有相对不同的变化趋势。最后,文中提出了一个光圆钢筋粘结强度折减公式,与实验值符合较好。
Ultra-high toughness cement-based materials (UHTCC) doped with nano-silica and steel fibers have good mechanical properties and high temperature resistance. In order to explore the synergistic performance of UHTCC and steel bar after high temperature, the appearance and appearance of UHTCC with round bar and deformed bar under different high temperatures were observed and studied. The results show that the bond stress between UHTCC and steel bar gradually decreases with the increase of experiencing temperature. The ultimate bond stress of the bar has a negative correlation with the slippage. The UHTCC is loose and porous after high temperature, which leads to the increase of plastic deformation capacity The generation of large slip of steel bar; the bond stress between deformed steel bar and UHTCC is significantly larger than that of light round steel bar, and the bond stress between the two has a relatively different trend with the increase of temperature. Finally, a reduction formula of the bond strength of the round bar is proposed, which is in good agreement with the experimental data.