Adhesion at high temperature of FRP bars straight or bent at the end of concrete slabs

Confidence in the use of Fiber Reinforced Polymer (FRP) for Reinforced Concrete (RC) members in multi-story buildings, parking garages, and industrial structures is poor due to lack of provisions and calculation models taking account of fire condition. In the past, to contribute to refining existing codes for the design of FRP-RC structures, authors tested six concrete slabs reinforced with Glass FRP (GFRP) bars characterized by different values of concrete cover and anchoring length in fire condition. Recently, further three fire tests were carried out on concrete slabs reinforced with GFRP bars bent at the ends. The anchoring of the FRP bars in the zone of slab not directly exposed to fire at the end of the members revealed essential to ensures slab resistance, once in the fire exposed zone of slab the glass transition temperature was attained and the resin softening reduced the adhesion at the FRP-concrete interface