Using Boring to Postpone Debonding of CFRP-Composite Concrete Beams

AbstractOne of the key issues associated with bonding of carbon fiberreinforced polymer (CFRP) sheets to the tension side of reinforced concrete (RC) beams is the debonding of CFRP sheets that leads to premature and brittle failure of the structural member. Surface preparation of concrete cannot, however, prevent debonding of CFRP sheets while it also has its own problems, such as high cost, environmental pollution, handling difficulties, and prolonged construction operations. In this paper, boring is proposed as an alternative method for bonding strengthening plates onto a concrete surface that not only lifts the problems associated with common methods of surface preparation but will also postpone debonding far more efficiently. A total of 42 nonreinforced concrete beams in four groups, i.e., lacking flexural strengthening, without surface preparation, with surface preparation, and with boring method were tested under four-point loading. To further investigate the performance of the boring method propose...