Flexural behavior of fire-damaged concrete beams repaired with strain-hardening cementitious composite

This study proposes a method to repair fire-damaged concrete beams using strain-hardening cementitious composite (SHCC) and investigates their flexural behavior through full-scale tests. Eleven beams with different reinforcement ratios were fabricated. Eight beams were damaged in fire, and six of them were repaired using SHCC or basalt-fiber-reinforced polymer fabric. Three beams were used as control and not exposed to fire. All the beams were tested under four-point bending until failure. The results indicated that the proposed repairing method was capable of increasing the load-carrying capacity, stiffness, and crack resistance of fire-damaged beams. Repairing the side and bottom faces of the fire-damaged beams using SHCC increased the load-carrying capacity by 32%. To promote evaluation and repair of fire-damaged beams in engineering practices, a mechanical analysis was performed to derive engineer-friendly formulae for predicting the load-carrying capacity of repaired beams and validated against test data. This study will promote repair and evaluation of fire-damaged structures using SHCC.