Bending performance of TRC-strengthened RC beams with secondary load under chloride erosion

Abstract

Textile reinforced concrete (TRC) has good bearing capacity, crack resistance and corrosion resistance and it is suitable for repairing and reinforcing concrete structures in harsh marine environments. The four-point bending method was used to analyze the influence of the salt concentration, the damage degree and the coupled effect of the environment and load on the bending performance of TRC-strengthened beams with a secondary load. The results showed that as the salt concentration increased, the crack width and mid-span deflection of the beam quickly increased, and its bearing capacity decreased. As the damage degree increased, the early-stage crack development and mid-span deflection of the beam were less affected and the ultimate bearing capacity significantly decreased. In addition, the coupled effect of the environment and load on the beams with a secondary load was significant. As the sustained load increased, the ultimate bearing capacity of the strengthened beam decreased, and cracks developed faster in the later stage. In addition, the mid-span deflection of the beam decreased at the same load level because of the influence of the initial deflection due to the sustained load corrosion.

摘要

纤维编织网增强混凝土(Textile Reinforced Concrete, TRC)具有良好的承载、限裂和耐腐蚀的 能力,适用于海洋严酷环境下混凝土结构的修复加固。本文采用四点弯曲加载的方式,分析了盐水浓 度、损伤程度、环境和荷载耦合作用等因素对TRC 加固二次受力梁弯曲性能的影响。研究结果表明: 随着盐水浓度的增加,梁的裂缝宽度和跨中挠度发展较快,承载力有所降低;随着损伤程度的增大, 梁前期裂缝和跨中挠度的发展受影响较小,而其极限承载力有较大的降幅;此外,环境和荷载耦合作 用对二次受力梁有明显的影响。随着持载水平的增大,加固梁的极限承载力有所降低,加载后期梁的 裂缝发展较快。受持载腐蚀时的初始挠度的影响,在同级加载下梁的跨中挠度有所降低。