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通过四点弯曲试验,研究并分析了在干湿循环和持续荷载共同作用下CFRP加固高强混凝土梁的耐久性。干湿循环介质采用3.5%的Na Cl溶液,循环次数设置0次、40次、80次和120次,持载等级为未加固钢筋混凝土梁极限荷载的0%,30%和60%。试验结果表明:干湿循环和持载作用后,加固梁的性能发生劣化,破坏方式逐渐由混凝土表层破坏向胶层与混凝土之间的粘结破坏发展;加固梁的极限荷载、跨中极限挠度、CFRP极限应变整体呈下降趋势,后期刚度显著降低,且随着持载等级提高,退化程度进一步加剧。
Through the four-point bending test, the durability of CFRP-reinforced high-strength concrete beams under the joint action of dry and wet cycles and continuous loads was studied and analyzed. The wet and dry circulation medium uses 3.5% NaCl solution, and the cycle times are set 0, 40, 80 and 120 times. The loading level is 0%, 30% and 60% of the ultimate load of unreinforced reinforced concrete beams. The test results show that the performance of the reinforced beam deteriorates due to the wet-dry cycle and the load-carrying effect, and the failure mode gradually develops from the destruction of the concrete surface layer to the bond between the rubber layer and the concrete; the ultimate load and the mid-span limit deflection of the reinforced beam. The overall limit strain of CFRP showed a downward trend, and the stiffness at the later stage was significantly reduced. With the increase of the load carrying level, the degree of degradation was further aggravated.