Study on the mechanical performance of TRC-strengthened RC beams under a salt freeze–thaw environment

The issue of the freeze–thaw has significantly affected the safety of reinforced concrete (RC) structures. Strengthening is an effective method to improve the safety performance of RC structures. To investigate the freeze–thaw resistance of RC beams strengthened with textile-reinforced concrete (TRC), the crack pattern, failure mode, load–deflection behavior, and bearing capacity of TRC-strengthened RC beams under a salt freeze–thaw environment were studied. The test parameters included the number of freeze–thaw cycles, installation method (cast-in-place versus precast), and sustained loading. The test results showed that the failure mode of the TRC-strengthened beam changes from flexural failure to shear failure due to freeze–thaw cycles. The installation method also affected the failure mode of the beams. The beam prepared using the precast method exhibited debonding failure, whereas the beam prepared using the cast-in-place method exhibited shear failure. When the freeze–thaw cycles exceeded a certain number or the sustained load surpassed a certain value, the crack control ability of the TRC weakened. The freeze–thaw cycle changed the load–deflection curve of the TRC-strengthened beam from a typical three-stage form to an approximate line. The ultimate load of the TRC-strengthened beam decreased with an increase in the number of freeze–thaw cycles. The ultimate load was also affected by the sustained load: the greater the sustained load, the greater the decrease in the ultimate load.