Bond Enhancement for FRP Pile Repair in Tidal Waters

Vacuum bagging and pressure bagging are established techniques used by the composites industry for fabricating components. This paper describes a study that explored the adaptation of these techniques for improving the FRP-concrete bond in the repair of partially submerged piles. Prototype vacuum bagging and pressure bagging systems were developed and bond improvement assessed from results of pullout tests on full size piles repaired under simulated tide in the laboratory. Pressure bagging gave better bond and was found to be simpler because it did not require an airtight seal. A field demonstration project was conducted in which pressure bagging was used in combination with two different GFRP systems to repair two corroding piles supporting the Friendship Trails Bridge across Tampa Bay. Inspection of the postcured wrap showed no evidence of air voids. The study demonstrates that techniques developed by the composites industry may be readily adapted to provide effective and inexpensive means for improving FRP-concrete bond.