碳纤维布加固钢筋混凝土梁剥离检测试验研究

Experimental Study on Debonding Defects Detection of CFRP-strengthened RC Beam

利用碳纤维增强复合材料(CFRP)对混凝土梁进行外部加固技术的应用日益广泛。CFRP加固钢筋混凝土梁因纤维端部应力集中而易发生早期的片材端部剥离破坏,对界面剥离进行有效检测具有重要意义。该文提出了基于压电驱动与应力波测量的CFRP与混凝土梁之间的界面剥离损伤监测方法,对CFRP补强钢筋混凝土梁进行四点弯试验,对试件从裂缝开始出现,直至最终破坏整个过程中各压电陶瓷片的测量响应进行分析,并定义损伤指标。结果表明,提出的界面剥离缺陷检测方法可对CFRP加固混凝土梁界面剥离发生、发展全过程进行有效监测,为预警提供了帮助。

The applications of the carbon fiber reinforced polymer (CFRP) material to the strengthening and retrofitting of reinforced concrete (RC) structures is becoming more and more extensive. The interface debonding at the end of CFRP sheet between CFRP and concrete due to stress concentration usually leads to a brittle failure. It is of great significance to detect the interface debonding effectively. In this study, a novel interface debonding monitoring technology for CFRP-strengthened RC beams under flexure is proposed on the basis of the stress wave measurement using piezoelectric lead zirconate titanate (PZT) patches as actuators and sensors. The CFRP-strengthened RC beam is tested under four-point flexure, and the measurement response of the PZT patches from the initiation of cracks to the final failure is analyzed and the damage index is defined. The test results show that the proposed interface debonding monitoring method can effectively monitor the occurrence and development of the interface debonding of CFRP-strengthened RC beam and provide assistance for early warning of the conditions of CFRP-strengthened RC structures.