Externally Bonded FRP Composites of RC Structures

该项目的目的是为混凝土结构的修复提供实施外部粘结FRP加固所需的工程科学，但构件受到压缩的情况除外，其中强度和延性的增强是混凝土侧向约束的结果。感兴趣的材料形式是由干纤维或预浸料制成的高度柔性片材，可以通过聚合物树脂进行最小的表面处理后粘附到混凝土表面。纤维为高强高模量，如碳、芳纶等。该项目的方法论包括主要基于拉伸钢筋混凝土试件的实验和分析研究。试验在机械条件（反复和持续加载）和环境条件（热循环和暴露于恶劣环境）后的准静态条件下进行。实验程序是必要的，以量化外部粘结FRP加固对混凝土抗裂性的影响，并评估长期加固性能。耐久性研究的一部分是确定FRP加固的存在是否促进/抑制混凝土中钢筋的降解（即，当FRP由导电纤维制成时，电偶腐蚀）。考察了各种材料形态、修复时的条件和制备条件。主要测量包括载荷、应变、界面分层、裂纹张开和电导率。该项目是在制造业和建筑业的合作下进行的，目的是获得适当的材料，并利用现场应用作为实验室研究结果和模型验证的试验台。＊＊＊

9506736 Nanni The objective of this project is to provide the engineering science necessary for the implementation of externally bonded FRP reinforcement for the repair of concrete structures, except for the case of members subjected to compression where enhancement of strength and ductility is the result of lateral confinement of concrete. The material forms of interest are highly flexible sheets made of dry fibers or prepregs that can be adhered to a concrete surface after minimum surface preparation by means of a polymeric resin. The fibers are high-strength and high-modulus such as carbon and aramid. The methodology of the project consists of an experimental and analytical study based primarily on tensile reinforced concrete specimens. Tests are conducted under quasi-static conditions after mechanical conditioning (repeated and sustained loading) and environmental conditioning (thermal cycling and exposure to aggressive environments). The experimental program is necessary to quantify the effects of externally bonded FRP reinforcement on concrete resistance to cracking and to assess long-term strengthening performance. A part of the durability study is to determine whether the presence of FRP reinforcement promotes/inhibits degradation of steel reinforcement in concrete (i.e., galvanic corrosion when FRP is made of conductive fibers). Various material forms, conditions at time of repair and preparation conditions are investigated. Primary measurements include load, strain, interfacial delamination, crack opening, and electrical conductivity. The project is conducted with the collaboration of the manufacturing and construction industry in the intent of securing suitable materials and of using field applications as a test bed for laboratory findings and verification of modeling. ***