Performance of Full-Scale RC T-Beams Strengthened with a Carbon-FRCM System under Fire Exposure

This study evaluates the structural and thermal performance of full-scale reinforced concrete (RC) T-beams strengthened with fabric-reinforced cementitious matrix (FRCM) systems subjected to a 180-min fire, in accordance with ASTM standard fire test methods. The fire-exposed beams were compared against identical configurations previously tested at room temperature. Five beams were subjected to a four-stage experimental sequence, including fire and cooling, to capture the complete structural response. FRCM layers acted as a significant thermal barrier, delaying reinforcement exceeding 400°C by more than 1 h compared with the control beam. All fire-exposed beams maintained stability under sustained loads, including a control beam loaded to 49% of its ultimate room-temperature capacity. As high temperatures weaken the textile–mortar bond, the system relies on mechanical anchorage within cooler support regions. The textile grid utilization level governs this mechanism, although sensor damage prevents the specific quantification of textile effectiveness during active heating. Beyond structural gain, FRCM enhances fire resistance by thermally shielding concrete and reinforcement more effectively than resin-based fiber-reinforced polymer systems.