Investigation of durability and surface preparation associated defect criticality of composites bonded to concrete

Although fiber reinforced polymer (FRP) composites are extensively used for the rehabilitation of concrete infrastructure there is a critical lack of information regarding the effect and criticality of defects making both inspection and assessment of integrity over the long-term difficult. In addition current empirical guidelines provide no guidance regarding progression over time, nor do they provide any guidance as related to environmental exposure effects. This paper reports on the use of a fracture based methodology for determination of criticality and discusses some results based on defect type associated with surface preparation, and exposure to a number of environments. It is shown that surface preparation has a significant effect on both fracture energy release rate and rate of crack propagation which can be accelerated by exposure. A damage tolerance approach to design is advocated based on an effect of defects methodology.