碳纤维增强复合材料加固混凝土粘结性能试验

碳纤维增强复合材料(carbon fiber reinforced polymer, CFRP)加固混凝土技术在桥梁工程与建筑工程中有大量应用，而直接影响工程结构加固维修的关键因素是其界面粘结性能，因此开展相关试验研究对保障工程安全具有重大意义。以一种基于专门设计的试验装置进行弯曲剪切试验来研究CFRP-混凝土界面的粘结性能。利用数字图像相关(digital image correlation, DIC)法得到的应变场确定碳纤维布的脱粘长度，同时对碳纤维增强材料的性能进行了理论分析，探讨了试验中的力学响应。结果表明：弯剪破坏的原因是弯矩的增大导致界面粘结强度和极限荷载的降低。通过对比弯剪试验和理论应变分布曲线，证明试验的有效性。粘结区在弯曲作用下产生的正应力有一个固定的有效区域，在该区域以外不会产生正应力。因此，在工程应用中，确定碳纤维布板的剥离长度可以减少维护工作，碳纤维布-钢筋混凝土在受弯曲和拉伸的共同作用下，可以在加载端有效应力区域内进行再加固，增加使用寿命。

Tests on Bonding Properties of Carbon Fiber Reinforced Polymer Reinforced Concrete

Carbon fiber reinforced polymer (CFRP) reinforced concrete technology has been widely used in bridge engineering and construction engineering. The key factor that directly affects the reinforcement and maintenance of engineering structure is its interface bonding properties. Therefore, it is of great significance to carry out relevant experimental research to guarantee engineering safety. The bonding properties of CFRP-concrete interface was investigated by bending shear tests based on a specially designed test device. Debonded length of CFRP was determined by strain field obtained by the digital image correlation (DIC) method. Theoretical analysis of CFRP performance was also conducted to probe mechanical response in these tests.The results reveal that the bending shear failure is due to the increase of the bending moment leading to the reduction of the interface bond strength and ultimate load. By comparing the strain distribution curves of bending shear tests and the theoretical strain distribution curve, the validity of the test is proved. There is a fixed effective area for the normal stress generated by the bending action of the bonding area, and normal stress will not be generated beyond this area. Therefore, in engineering applications, the determination of the stripping length of CFRP plates can reduce the maintenance work, and the CFRP-reinforced concrete subjected to the combined action of bending and tension can be re-reinforced in the effective stress area of the loading end to increase the service life.