Adhesive thickness effect upon the CFRP plate-concrete interface bond behaviours

Abstract Bonding behavior at the interface between concrete and carbon fiber reinforced polymer (CFRP) is very important for the FRP efficiency in concrete structure strengthening. Influences of the adhesive thickness upon BP is rarely studied in the previous literature. In this paper, based upon testing data of 8 single shear specimens, a finite element (FE) method is investigated to analyze debonding in CFRP-concrete interface. By analyzing the specimen failure mode, the FRP strain distributions along bond length, and ultimate bearing capacity (UBC), influences of adhesive thickness on bonding behavior were investigated. Our data prove that the adhesive thickness has significant effects upon bonding behaviors between concrete and CFRP interface. With an increment of adhesive thickness, bond strength increases and reaches the maximum at 3 mm. If the adhesive thickness is > 3 mm, bond strength of the low-grade concrete specimen is reduced. However, the high-grade concrete specimen bond strength continues to increase, but the rate of increase decreases.