水环境下钢筋与混凝土黏结性能试验研究

Experimental Research on Bond Behavior between Reinforcement and Concrete in Water Environment

混凝土中的自由水对其力学性能会产生影响,为研究不同浸泡时间下钢筋与混凝土黏结性能的变化规律,建立黏结-滑移本构模型,开展了水环境下钢筋与混凝土黏结性能试验研究。试验中的设计参数包括浸泡时间(28、90、180、270、360 d)和混凝土强度等级(C20和C40),共完成了10组试件的黏结-滑移性能试验。研究结果表明:水环境对混凝土含水率、抗压强度、劈裂抗拉强度会产生不同影响,水环境下混凝土立方体的抗压强度、劈裂抗拉强度与浸泡天数的对数值基本呈线性关系;由于箍筋的约束,水环境下钢筋与混凝土试件黏结-滑移曲线存在明显的下降段;通过试验数据的回归分析,给出了不同浸泡时间下的黏结强度及滑移量、残余强度的计算公式,经计算结果与试验结果的比较,验证了所给公式的适用性。

Free water in concrete has effects on mechanical properties of concrete.In order to study the bond behavior be-tween reinforcement and concrete in water environment,a total of thirty pullout specimens with deformed steel bars were im-mersed in water and then the pullout tests were carried out.The design parameters considered in this study were soaking time(28,90,180,270、360 d)and concrete strength(C20 and C40).The experimental results indicate that the moisture content of concrete,compressive strength and splitting tensile strength of concrete cubes are affected by water environment.Moreover,the compressive strength and the splitting tensile strength of concrete cubes varies linearly with the logarithm of soaking time.Due to the confinement of stirrups,the descent segment of bond-slip curve drops slowly.Based on the test data,the expressions of bond strength and the corresponding slips,residual strength with different soaking time were estab-lished.The applicability of proposed equation was validated by comparing the calculation results with the experimental datum.