侵蚀环境下TRC约束混凝土与钢筋的黏结性能

Bonding Properties between TRC Confined Concrete and Steel Bar under Erosion Environment

纤维编织网增强混凝土(TRC)约束条件下钢筋与混凝土的黏结性能是评价TRC加固效果的重要因素之一.基于电化学锈蚀和拔出试验结果,从锈胀裂缝、破坏模式、黏结强度、黏结失效机理的角度对比分析了侵蚀环境下未约束和TRC约束混凝土与钢筋的黏结性能,并从能量角度对黏结性能作了进一步阐释.结果表明:TRC约束可以有效限制锈胀裂缝的开展,TRC约束试件的锈胀裂缝宽度明显降低;TRC约束试件的破坏模式由混凝土劈裂破坏转变为具有一定延性特征的劈裂-拔出破坏;未约束试件的极限黏结强度随钢筋锈蚀率增加而极大降低,TRC约束则可以有效控制该降低趋势;从能量角度得到的分析结果与试验结果具有较好的一致性.

The bonding properties between steel bar and concrete confined by textile reinforced concrete(TRC) is one of the important factors for evaluating the TRC reinforcement effect. Based on the results of electrochemical corrosion and pull-out tests, the bonding properties between the unconfined or TRC confined concrete and steel bar under erosion environment were comparatively analyzed in terms of the corrosion-induced crack, failure mode, bonding strength and bonding failure mechanism. The bonding properties were further illustrated from the point of energy. The results show that TRC confinement can effectively control the development of corrosion-induced crack, so the crack width decreases significantly for the TRC confined specimens. The failure mode of the TRC confined specimens is changed from the splitting of concrete to the splitting-pull out, which has a certain ductile failure characteristic. For the unconfined specimens, the great degradation of the ultimate bonding strength is observed as the corrosion rate of steel bar increases, while the degradation trend is effectively controlled because of TRC confinement. The results from the energy analysis have a good consistency with the test results.