Engineering Structures ( IF 5.5 ) Pub Date : 2021-01-13 , DOI: 10.1016/j.engstruct.2020.111718 Mu-Wang Wei , Jian-He Xie , Jiang-Lin Li , Chen-Yu Xiang , Pei-Yan Huang , Feng Liu
Carbon fibre-reinforced polymer (CFRP) plates are widely used to strengthen reinforced-concrete (RC) structures. At present, most studies focused on the short-term performance of strengthened RC beams with a prestressed CFRP plate, and very limited information is available on their durability, which is of importance in certain cases, such as high-piled wharfs and bridges in marine environments. This study investigates the effects of chloride environment exposure on the flexural performance of strengthened RC beams with self-anchored prestressed CFRP plates. In total, seven RC beams, four of which were strengthened by a self-anchored prestressed CFRP plate, were fabricated and tested under three-point bending. The testing parameters included 25% and 40% prestress level of the ultimate tensile strength of the CFRP plate, 5% and 10% tensile steel rebar corrosion ratio of mass loss and 10% and 20% anchor corrosion ratio in the chloride environment. The evolution of time-dependent prestress losses in the strengthened beam was determined, and the flexural behaviour of the strengthened beams was analysed. A theoretical model is proposed to predict the flexural strength of prestressed CFRP strengthened RC beams in a chloride environment. The experimental results indicated that the coupling of the corrosion expansion of the metal anchor and rebar in the chloride environment had a large negative effect on the flexural performance of the beams strengthened by the self-anchored prestressed CFRP plates. After exposure to the chloride ion solution, the failure mode of the RC beams strengthened by the prestressed CFRP changed from concrete crushing in the compression section to anchor pullout. The proposed model, which considered the effect of a chloride environment to predict the flexural strength of the strengthened beams, agreed well with the test results.
中文翻译:
氯离子暴露对自锚式预应力CFRP板加固钢筋混凝土梁抗弯性能的影响
碳纤维增强聚合物(CFRP)板被广泛用于增强钢筋混凝土(RC)结构。目前,大多数研究都集中在预应力CFRP板加固钢筋混凝土梁的短期性能上,关于其耐久性的信息非常有限,这在某些情况下非常重要,例如高桩码头和海上桥梁。环境。这项研究调查了暴露于氯化物环境对带有自锚式预应力CFRP板的钢筋混凝土梁的抗弯性能的影响。总共制造了7条RC梁,并在三点弯曲下对其进行了测试,其中4条通过自锚预应力CFRP板进行了加固。测试参数包括CFRP板极限抗拉强度的25%和40%的预应力水平,在氯化物环境下,质量损失为5%和10%的钢筋螺纹钢腐蚀率和10%和20%的锚固腐蚀率。确定了加固梁中随时间变化的预应力损失的演变,并分析了加固梁的抗弯性能。提出了一个理论模型来预测在氯化物环境下预应力CFRP加固的RC梁的抗弯强度。实验结果表明,在氯化物环境中,金属锚固件和钢筋的腐蚀膨胀耦合对自锚式预应力CFRP板加固的梁的抗弯性能有很大的负面影响。暴露于氯离子溶液后,预应力CFRP加固的RC梁的破坏模式从受压段的混凝土碾压变为锚固拉拔。所提出的模型考虑了氯化物环境对加强梁的抗弯强度的预测,与试验结果非常吻合。