疲劳、冻融和锈蚀综合作用下川藏地区RC梁粘结破坏机理研究

川藏地区钢筋混凝土（RC）结构面临复杂严酷的气候和地理环境，其长寿命保障面临巨大挑战。特别是疲劳荷载、冻融和钢筋锈蚀的综合作用影响钢筋与混凝土粘结，导致结构服役性能与寿命降低，然而该综合作用下钢筋混凝土梁的粘结破坏机理尚不清楚。本项目针对疲劳、冻融和锈蚀综合作用下川藏地区钢筋混凝土结构粘结性能劣化问题，采用微/宏观试验研究与多尺度数值模拟相结合的方法，开展钢筋混凝土梁承受疲劳、冻融和锈蚀综合作用后的微观机理试验，揭示该综合作用下钢筋-混凝土界面损伤机理；开展疲劳、冻融和锈蚀综合作用后钢筋混凝土梁的粘结破坏试验，建立考虑该综合作用的粘结应力-滑移本构关系；结合钢筋混凝土梁宏-细观多尺度数值模拟方法，分析疲劳、冻融和锈蚀综合作用下钢筋混凝土梁的粘结破坏机理，据此提出该综合作用下钢筋混凝土梁的粘结疲劳寿命预测方法，为川藏地区钢筋混凝土结构耐久性评估及其长寿命保障奠定基础。

In Sichuan-Tibet region, reinforced concrete (RC) structures are subjected to the harsh climate and geographical environment, which challenges its long-life guarantee. Especially the actions of fatigue loading, freeze-thaw cycles and steel corrosion, influence the bond behavior between the concrete and steel, leading to the decreases in the service performance and service life. However, the bond failure mechanism of RC beams under these actions is obscure. This project will focus on the deterioration of the bond behavior of RC beams in Sichuan-Tibet region, under the actions of fatigue, freeze-thaw and steel corrosion. The micro/macro experimental research and multi-scale numerical simulation will be conducted. The micro mechanism test of RC beams under these actions are carried out to reveal the damage mechanism of the steel-concrete interface. The bond stress-slip curves considering the actions of fatigue, freeze-thaw and steel corrosion will be evaluated by the bond failure test. Based on the multi-scale numerical simulation method for the RC beams, the bond failure mechanism of RC beams under these actions will be analyzed, and then the bond-fatigue life prediction method will be proposed. This project aims to provide the foundation for durability evaluation and long-life guarantee of RC structures in Sichuan-Tibet region.