CFRP筋与海水海砂混凝土粘结性能试验与机制分析

Experiment on bond performance between CFRP bar and seawater sea sand concrete and its working mechanism

  • 摘要: 通过碳纤维增强树脂复合材料(CFRP)筋与海水海砂混凝土的中心及偏心拉拔试验,对比了CFRP筋在不同条件下拔出时的粘结应力及滑移值大小,得到完整的CFRP筋/海水海砂混凝土粘结-滑移曲线,同时分析了CFRP筋在混凝土中发生滑移时会产生的若干破坏模式,在此基础上对粘结-滑移曲线不同受力阶段特点进行了分析。同时,采用正交试验的方式,获得了不同因素对CFRP筋/混凝土粘结强度的影响程度。试验表明,CFRP筋/混凝土粘结力中摩擦力的占比较大,且粘结强度最主要的影响因素是混凝土的强度等级。除了传统拉拔试验中会出现的受力筋拉出破坏和混凝土劈裂破坏外,CFRP筋还会由于自身的外形、工艺及力学性能的影响,发生自身破坏。对不同破坏模式、受力筋外形的三种CFRP筋/海水海砂混凝土粘结-滑移曲线,采用多种理论表达式进行对比,最终得到不同条件下CFRP/海水海砂混凝土的粘结-滑移本构关系表达式。

     

    Abstract: In order to study the bond performance between carbon fibre reinforced polymer (CFRP) bars and seawater sea sand concrete, the pull-out test of CFRP and seawater sea sand concrete was carried out in different conditions and the bond-slip curve was obtained. During the test, different failure modes were observed and concluded to analyze the failure mechanism between CFRP bars and seawater sea sand concrete. The influence of different factors on the bond performance was analyzed based on orthogonal experiment. The results show that the strength of concrete is the most important factor affecting the bond strength, and the friction plays a large part in the bond stress. Besides the pull-out damage and concrete splitting damage, CFRP damage exists in the test due to the production process and mechanical performance of CFRP itself. Based on the results above, three types of bond-slip constitutive relation expression of CFRP/seawater sea sand concrete were finally concluded by curve fitting and comparing.

     

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