An Analytical Model of FRP-Concrete Bond Deterioration in Moist Environment

摘要

Debonding of FRP from concrete substrate can lead to premature failure of the FRP repaired or retrofitted concrete structures. Therefore, FRP-concrete bond is a major factor affecting the performance of FRP strengthened concrete members. Experimental studies show that moisture plays an important role in the reliability of the bond between FRP and concrete. In this study, a cohesive zone model (CZM) of debonding along the FRP-concrete interface under peel load was analytically established by using a linear elastic separation-stress law. The interface region relative humidity (IRRH) was selected as the primary factor to study the bond durability of FRP/concrete bond. Based on a nonlinear deterioration model, the analytical solution of the CZM was used to determine critical load vs. crack length relations (P-a curves) of Modified Double Cantilever Beam (MDCB) specimens at different moisture exposure durations. The good agreement with experimental data indicates that the CZM for FRP-concrete joint is an efficient way to analyze bond behavior in moist environments.