Investigation of flexural behaviour of the damaged reinforced concrete beam strengthened by MPC pasting glass fiber reinforced textile

With the extension of building service life and the erosion of various environments, the demand for building reinforcement is increasing. This study aims to investigate the flexural performance of reinforced concrete (RC) beams strengthened with magnesium phosphate cement (MPC) combined with glass fiber-reinforced textile (GFRT). Through experiments and analysis, the study examined the flexural capacity, midspan deflection, crack development, and failure modes of RC beams with different concrete strength grades (including coral aggregate RC beams, basic magnesium sulfate RC beams (BMRCB), and ordinary Portland RC beams) before and after strengthening. The results show that the MPC-GFRT strengthening significantly increased the crack moment of the beams, with enhancements ranging from 125.0 to 200.0%, and the low-strength concrete beams exhibited more pronounced increases. The ultimate bending moment recovery rate was between 86.9 and 102.2%, indicating that the MPC-GFRT strengthening effectively restored the flexural performance of the damaged beams. In addition, the study optimized the calculation models for the short-term stiffness and ultimate flexural capacity of the strengthened beams, further verifying the feasibility of using MPC instead of epoxy resin adhesive for concrete reinforcement.