Fire performance of reinforced concrete beams strengthened with CFRP sheets bonded with an inorganic adhesive

Considering softening temperatures of ordinary organic epoxy adhesives are too low, this study develops an inorganic adhesive which strength at 600°C is not lower than that at normal room temperature. Four reinforced concrete (RC) beams strengthened with CFRP sheets bonded with the inorganic adhesive are tested. The fire protection of the CFRP sheets is done using the thick-type fireproofing coatings for tunnel (TFCT) and steel structure (TFCSS) respectively. All specimens are tested in the furnace together. Specimens are exposed to fire for 1.5 hours in according to the ISO834 standard fire curve, and then naturally cooled for 1 hour. CFRP sheets at center point of bottom surface of beams are 300∼470°C, and the corresponding displacements at mid-span are 1/1400∼1/318 of the actual span. The CFRP sheets keep a good state and are tightly bonded on RC beams by the inorganic adhesive after fire. Temperature and deformation are analyzed by ABAQUS, and the simulation and measured results are in good agreement. The results indicate that, under the protection of fireproof coating, the CFRP sheets work well in cooperation with RC beams and slabs during fire. TFCSS is inferior to TFCT because the former is easier to drop and crack in fire. Analysis method of the finite element supplies a good way to temperature field and deformation calculation of structures in fire.