湿热环境下CFL-混凝土界面疲劳本构关系研究

发布时间：2018-01-10 14:19

本文关键词：湿热环境下CFL-混凝土界面疲劳本构关系研究　出处：《华南理工大学》2014年硕士论文　论文类型：学位论文

【摘要】：纤维增强复合材料（Fiber Reinforced Polymer，简称FRP）以其材质轻、可设计、强度高、抗疲劳性能好、耐腐蚀和耐久性好等优点，已广泛应用于混凝土结构的加固修复工程中。界面层作为FRP与混凝土之间的过渡层，是从混凝土向FRP传递应力的桥梁。以往的实验研究结果表明，FRP-混凝土界面的剥离破坏是该类加固构件的主要破坏形式之一，而界面层的性能直接影响FRP加固混凝土构件的承载能力和疲劳性能。因此，开展FRP-混凝土界面的疲劳本构关系研究具有重要的科学意义和工程应用价值。本文采用本课题组发明的新型FRP片材—碳纤维薄板（Carbon Fiber Laminate，简称CFL）与钢筋混凝土（RC）梁的粘结界面作为研究对象，考虑我国南方和沿海等地区的湿热大气环境对公路运营桥梁的影响，采用实验研究与理论分析相结合的方法，探讨在湿热环境下CFL-混凝土界面的疲劳本构关系。主要研究内容和结论如下：（1）根据广东地区的亚热带气候特点，制定相应的湿热环境条件，对试件进行环境预处理，然后通过双剪疲劳实验，分别对试件的疲劳寿命、荷载位移曲线、试件相对滑移的演化规律及峰值荷载下CFL上应变的演化规律进行了探讨。研究结果表明，高温高湿环境会使界面的变形增大、疲劳寿命降低，而且极限位移也会增大。（2）通过对双剪疲劳实验全过程的跟踪和观测，，发现在经过湿热环境预处理后，CFL-混凝土粘结界面的疲劳破坏过程呈现明显的三阶段演化规律，即其疲劳破坏由初期的混凝土开裂、界面稳定剥离、失稳剥离三阶段构成。（3）根据双剪疲劳实验结果，初步探明了CFL-混凝土界面粘结强度的退化规律。在此基础上，利用双剪疲劳实验数据和Popovics模型，提出了湿热环境下CFL-混凝土界面的疲劳本构关系式。
[Abstract]:Fiber Reinforced Polymer (FRP) is a kind of fiber reinforced composite material, which has the advantages of light material, design ability, high strength and good fatigue resistance. Due to its advantages of good corrosion resistance and durability, it has been widely used in the reinforcement and restoration of concrete structures. The interface layer is used as the transition layer between FRP and concrete. The experimental results show that the debonding failure of FRP- concrete interface is one of the main failure forms of this kind of strengthened members. The performance of interface layer directly affects the bearing capacity and fatigue performance of concrete members strengthened by FRP. It is of great scientific significance and engineering value to study the fatigue constitutive relation of FRP-concrete interface. In this paper, a new FRP sheet, carbon Fiber Laminate, is developed by our team. The bond interface between CFL) and RC beams is taken as the research object. The influence of the humid and thermal atmosphere environment on the highway operation bridges in the south and coastal areas of China is considered. In this paper, the fatigue constitutive relationship of CFL- concrete interface under humid and hot environment is studied by combining experimental research with theoretical analysis. The main contents and conclusions are as follows: 1) according to the characteristics of subtropical climate in Guangdong, the corresponding conditions of humid and thermal environment were established, and the samples were pretreated by environmental pretreatment, and then the fatigue life of the specimens was tested by double shear fatigue test. The load-displacement curve, the evolution law of relative slip of specimen and the evolution law of strain on CFL under peak load are discussed. The results show that the deformation of interface will increase in high temperature and high humidity environment. The fatigue life decreases and the limit displacement increases. 2) through tracking and observing the whole process of double shear fatigue experiment, it is found that the fatigue failure process of CFL- concrete bond interface after preconditioning in humid and hot environment shows an obvious three-stage evolution law. That is to say, the fatigue failure consists of three stages: initial crack of concrete, stable exfoliation of interface and unsteady exfoliation. 3) based on the experimental results of double shear fatigue, the degradation law of CFL- concrete interfacial bond strength is preliminarily proved. Based on this, the double shear fatigue test data and Popovics model are used. The fatigue constitutive equation of CFL-concrete interface in humid and hot environment is presented.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U441.4

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