Flexural Behavior of Textile Reinforced Mortar-Strengthened Reinforced Concrete Beams Subjected to Cyclic Loading

Abstract

Textile-reinforced mortar (TRM) is used to strengthen reinforced concrete (RC) structures using a textile and inorganic matrix. TRM is a part of textile-based composites; the basic structural behaviors, application methods, and methodologies for the extension of actual structures in TRM were studied. However, structural behavior and performance verification which depict the long-term service situation and fatigue is limited. Therefore, this study, verified the flexural behavior of TRM-strengthened beams and their fatigue performances using carbon- and alkali-resistant (AR) glass textiles through 200,000 load cycles. TRM-strengthened beams were applied to an optimization strengthening method which consisted of whether the textile was straightened. According to the test results, the strengthening efficiency of TRM-strengthened beams when subjected to cyclic loading was lower than that of the monotonic loading, except for the straightened carbon textile specimen. The average efficiency of the AR-glass textile (straightened and non-straightened) and carbon (non-straightened) was 0.86 compared to the TRM-strengthened beam subjected to monotonic loading in terms of flexural strength. In the case of deflection, the average efficiency of the AR-glass textile type was similar to the monotonic loading test results, while that of the non-straightened carbon textile was improved. The Ca-S specimen that was used to straighten the carbon textile showed a reliable structural performance with a strength efficiency of 0.99 and a deflection efficiency of 0.97 compared to the monotonic load test. Therefore, TRM strengthening using a straightened carbon textile is expected to be sufficient for the fatigue design of TRM-strengthened beams.