Investigation of the bond behavior of flax FRP strengthened RC structures through double lap shear testing

This paper focuses on the characterization of the bond behavior of adhesively bonded Flax Fiber Reinforced polymers (FRP) to concrete substrate. An experimental investigation has been done comparing flax and glass FRP bonded to concrete using a double shear test configuration. Flax composites appear to show the same interface behavior as the usual synthetic fiber reinforcement. Analyses of the strain and shear stress distribution along the interface reveal behavior differences.To investigate if the same models could be accurately used in the case of flax FRP or if a new model is needed, experimental results of debonding load and efficient bonded length have been compared to the values of four different prediction models. Coefficients calibrated for the flax composite lead to an underestimation of the efficient bonded length for the glass composite.