钢绞线与混凝土的粘结腐蚀疲劳损伤行为

发布时间：2018-03-21 04:25

本文选题：钢绞线　切入点：粘结　出处：《中国矿业大学》2015年硕士论文　论文类型：学位论文

【摘要】：许多预应力混凝土结构须要承受疲劳荷载与腐蚀环境的共同作用,这将导致钢筋和粘结发生不收敛的腐蚀疲劳耦合损伤,结构抗力因此而不断退化。本文以氯盐腐蚀环境为背景,以有粘结钢绞线预应力混凝土结构为对象,基于长期腐蚀疲劳试验模拟,研究钢绞线与混凝土粘结的腐蚀疲劳损伤特征和演化规律,从而为预应力混凝土结构耐久性评估与设计提供参考。通过对掺盐腐蚀预应力混凝土粘结试件进行长期疲劳加载以形成腐蚀疲劳损伤,然后进行静力拉拔试验,据此分析了混凝土和钢绞线的损伤特征及破坏特征,考察了粘结滑移曲线特征及粘结强度随腐蚀和疲劳作用强度退化的规律。采用恒电流法加速腐蚀钢绞线,并同时对粘结试件施加疲劳荷载,以此研究粘结的腐蚀疲劳损伤特征以及腐蚀对疲劳寿命的影响规律。结果发现,同时承受腐蚀和疲劳作用的粘结试件会发生混凝土劈裂及钢绞线拔出的现象,此时标志着试件达到了疲劳寿命终止状态;粘结疲劳寿命随疲劳应力幅和腐蚀疲劳强度因子均呈指数型衰退的变化规律;通过对试验结果的拟合,建立了随疲劳应力幅和腐蚀疲劳强度因子变化的粘结寿命预计模型。根据前人研究结果,比较分析了钢绞线受拉性能和粘结性能二者的退化规律与模型,发现在腐蚀疲劳共同作用下,预应力混凝土构件承载力退化的控制因素是钢绞线的受拉性能,钢绞线与混凝土的粘结性能退化相对成为其次。
[Abstract]:Many prestressed concrete structures need to bear the joint action of fatigue load and corrosion environment, which will lead to non-convergent corrosion fatigue coupling damage of steel bar and bond. In this paper, the corrosion environment of chloride salt is taken as the background, the prestressed concrete structure of bonded steel strand is taken as the object, and the simulation of long-term corrosion fatigue test is carried out. The corrosion fatigue damage characteristics and evolution law of bond between steel strand and concrete are studied. So as to provide a reference for the durability evaluation and design of prestressed concrete structures. The corrosion fatigue damage is formed by long-term fatigue loading on the bonded specimens of salt corroded prestressed concrete, and then the static pull-out test is carried out. Based on this, the damage and failure characteristics of concrete and steel strands are analyzed, and the characteristics of bond-slip curve and the law of bond strength degradation with corrosion and fatigue strength are investigated. The constant current method is used to accelerate the corrosion of steel strands. At the same time, the fatigue load is applied to the bonded specimen, so as to study the corrosion fatigue damage characteristics of bond and the influence of corrosion on fatigue life. At the same time, concrete splitting and steel strand pull-out will occur in the bonded specimens subjected to corrosion and fatigue, which indicates that the specimen has reached the state of fatigue life termination. The change of bond fatigue life with fatigue stress amplitude and corrosion fatigue strength factor is exponential. The prediction model of bond life with the variation of fatigue stress amplitude and corrosion fatigue strength factor is established. According to the results of previous studies, the degradation laws and models of tensile and bond properties of steel strands are compared and analyzed. It is found that under the joint action of corrosion fatigue, the tensile behavior of steel strands is the controlling factor for the degradation of the bearing capacity of prestressed concrete members, and the degradation of bond performance between steel strands and concrete is the second.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU528

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