Fire behavior of full-scale CFRP-strengthened RC beams protected with different insulation systems

Abstract

In this paper, a series of experimental studies conducted to investigate the fire behavior of insulated full-scale carbon-fiber-reinforced polymers (CFRP)-strengthened reinforced concrete (RC) beams is presented. Four CFRP-strengthened RC beams, respectively insulated with a thick coating system, ultrathin coating system and calcium silicate board system, were tested under ISO834 standard fire exposure. The test results revealed that satisfactory fire endurance for CFRP-strengthened concrete beams can be obtained with the protection of the three systems. The major role of fire insulation materials is to delay the failure of adhesive in the early stage and reduce the performance degradation of concrete and internal reinforced bars after the bond failure of the CFRP–concrete interface. In addition, it was indicated that effective anchorages of CFRP and reasonable anchoring constructions of the insulation system played important roles in ensuring the fire-resistant capability of CFRP-strengthened concrete beams. Further, a detailed finite element model was developed as an alternative to the standard fire test. The predicted temperature and deflection results were in good agreement with the measured ones. Based on the case studies, insulation thickness, insulation thermal conductivity, CFRP amount and load ratio were proven to be the main influences of the fire resistance of insulated CFRP-strengthened beams.