基于AE技术的FRP增强混凝土缺口梁损伤断裂机理研究

Cracks is one of the major issues facing concrete structural engineering. Because of the property of light self-weight, high strength, good durability, easy construction and so on, FRP is an effective approach to reinforced concrete structure. The normal service performance of FRP strengthened concrete structures has been attracted much interest and many achievements have been made all over the world. Howerer, it is inadequate and unsuitable to study the fracture characteristics of notched concrete structures based on the traditional classical strength theory. In this research project, the fracture test of notched concrete beams strengthened with FRP will be carried out base on the real time and nondestructive acoustic emission (AE) technique, the optimum bond length of FRP will be obtained to different pre-set crack depth. Based on the model test results, in combination with mechanism analysis of concrete AE characteristics, explore the relationship between acoustic emission parameters and the crack growth rate to the fracture process of FRP strengthening notched concrete beams, deduce the damage and fracture evolution equation, which considers the AE signal parameters. At last, present a test procedure involving FRP reinforce concrete structure and fracture test, and establish a fracture model of FRP strengthening notched concrete beams. The studies will supplement and improve the fracture theory of concrete, and play a greater role in anti-cracking design and crack safety analysis of concrete structural engineering.

混凝土裂缝是工程建设面临的重大难题。由于纤维增强复合材料（FRP）自重小、强度高、耐久性好和施工简便等特点，成为修复加固混凝土结构的有效途径。各国学者已对FRP增强混凝土结构正常使用性能开展了大量的研究工作，然而，采用传统的强度理论研究带裂缝混凝土结构的断裂特性已不再适用。鉴于此，本项目基于实时动态的无损检测声发射（AE）技术，开展FRP增强混凝土缺口梁损伤断裂试验，确定不同裂缝深度所对应的最佳FRP粘结长度值。基于模型试验结果，结合混凝土材料声发射机理分析，探索FRP增强混凝土缺口梁断裂过程声发射率同裂纹扩展速率之间的关系，推导出考虑声发射信号参量的FRP增强混凝土缺口梁损伤断裂演化方程，最终提出一套FRP增强混凝土缺口梁的加固以及断裂测试方法，并建立FRP增强混凝土缺口梁断裂本构模型。研究结果将进一步补充和完善混凝土断裂理论，并在混凝土结构工程防裂设计及裂缝安全分析中发挥更大的作用。

混凝土裂缝是工程建设面临的重大难题。由于纤维增强复合材料（FRP）自重小、强度高、耐久性好和施工简便等特点，成为修复加固混凝土结构的有效途径。各国学者已对FRP增强混凝土结构正常使用性能开展了大量的研究工作，然而，采用传统的强度理论研究带裂缝混凝土结构的断裂特性已不再适用。鉴于此，本项目基于实时动态的无损检测声发射（AE）技术，开展FRP增强混凝土缺口梁损伤断裂试验，确定不同裂缝深度所对应的最佳FRP粘结长度值。研究结果进一步补充和完善了混凝土断裂理论，并在混凝土结构工程防裂设计及裂缝安全分析中发挥更大的作用。项目执行期内，共计发表学术论文9篇、申请国家发明专利4项、授权国家发明专利1项、获大禹水利科技进步一等奖1项、获中国航海科技特等奖1项。