冻融损伤混凝土与光圆钢筋黏结本构关系试验研究

为了研究冻融损伤混凝土与光圆钢筋黏结本构关系,对三种强度等级混凝土试件分别开展了快速冻融循环试验及拉拔试验,得到了不同强度等级、不同冻融循环次数下混凝土的抗压强度及其与光圆钢筋的黏结-滑移曲线。试验结果表明,不同强度等级及不同冻融循环次数的混凝土与光圆钢筋黏结-滑移曲线形状类似;对于相同强度等级试件,随着冻融循环次数的增加,峰值黏结强度、残余黏结强度和初始黏结刚度不断降低而峰值滑移不断增大;对于遭受相同冻融循环次数试件,混凝土强度等级越高,峰值黏结强度和残余黏结强度也越高,而峰值滑移变化规律不明显。最后建立了冻融损伤混凝土与光圆钢筋的黏结-滑移本构模型。上述结果对寒冷地区钢筋混凝土结构性能评定有参考价值。

Experimental study of bond-slip constitutive relationship between freeze- thaw damaged concrete and plain round bar

In order to study the bond-slip constitutive relationship between freeze-thaw damaged concrete and plain round bar, rapid freeze-thaw cycle experiment and pull-out experiment were carried out respectively, for concrete specimens with three kinds of strength grade. The compressive strength of concrete with different strength grades and different freeze-thaw cycles and the bond-slip curve with the plain round bar are also obtained. Experimental results show that the bond-slip curves of concrete with different strength grades are similar to those that subjected to different freeze-thaw cycles of plain round bar. With the increase of freeze-thaw cycles, the bond strength, the remaining bond strength and the initial bond stiffness decrease whereas the ultimate slip increases for the specimens with the same concrete strength grade, moreover with regard to the specimens subjected to the same freeze-thaw cycles, the bond strength and the remaining bond strength increase accompanied by the increase of concrete strength grade. A bond stress-slip relation for plain round bar in frost-damaged concrete has been proposed, which can provide a reference to the performance evaluation of reinforced concrete structure in cold area.