恶劣环境与荷载共同作用下FRP-高强混凝土的粘结耐久性

Durability of FRP-high Strength Concrete Adhesive Joints under Aggressive Exposure Conditions and Loads

通过试验,研究并分析了在冻融循环、干湿循环和持续荷载共同作用下,高强混凝土与CFRP(碳纤维增强复合材料)粘结界面的长期性能,为外贴CFRP加固海岸与近海高强混凝土结构的耐久性设计提供依据。通过分析加载剥离过程中的破坏方式、峰值荷载、加载端劣化剥离、有效粘结长度及粘结滑移关系等数据,研究了界面劣化规律。结果表明:由于高强混凝土有较高抗冻性,单纯冻融和干湿循环对界面的劣化作用很小;但是加上持续荷载后,粘结性能的劣化变得非常显著,且主要表现为加载端劣化剥离区域长度的增加。

This paper researches and analyzes the long-term performance of high-strength concrete-CFRP（carbon fiber reinforced polymer）interface under the combined impacts of freezethaw cycling,wet-dry cycling and sustained loads,in order to provide a basis for the durability design of coastal and offshore high strength concrete structures reinforced by CFRP.In the test,specimens are set every more 50freeze-thaw cycles and 20wet-dry cycles.The largest number of the freeze-thaw and wet-dry cycling are 300 and 120respectively.Three load levels are imposed：0%,35% and 70% of the initial stripping load of unconditioned control specimens.The trends of the failure mode,peak load,length of debonded area at the load-end,effective bond length and material law of the interface are analyzed.It is found that the degradation of the bond property caused by freeze-thaw and wet-dry cycles is limited,but it turned to be quite significant when sustained load is added.And the main mode of degradation is the increase of the length of debonded area at load-end.