| Corrosion of the steel reinforcement is the most widespread form of deterioration of reinforced concrete structures. Although current codes of practice adopt recommendations and precautions to avoid corrosion, evidence of the corrosion of steel in concrete continues to be reported in field situations. Traditional methods of repair are not only costly and time and labor consuming but also often vulnerable to the same deterioration mechanism as the original structure which requires a second and third generation of repairs. Hence, there is a need for a new repair technique that is durable and cost effective.; Advanced composite materials in the form of externally bonded carbon fibre reinforced polymer (CFRP) laminates have been successfully used in structural retrofitting and upgrading. However, little is known about the viability of using externally bonded CFRP laminates to repair corroded reinforced concrete beams at various levels of damage. The performance of CFRP repaired beams when exposed to corrosive environmental conditions after repair under a sustained load has received little attention in previous studies.; The present work was initiated to investigate, experimentally and analytically, the performance of corrosion-damaged reinforced concrete beams repaired with CFRP laminates. Experiments on twenty nine reinforced concrete beams (152 x 254 x 3200 mm) were undertaken. Test parameters included the time of corrosion exposure (0, 50, 110, 210, or 310 days), the loading condition during the corrosion exposure (corrosion under a sustained load or corrosion without load), and the external configuration of the CFRP repair scheme (flexural strengthening with a continuous wrapping or flexural strengthening with an intermittent wrapping). The test set-up, instrumentation, control, and specimen manufacturing were presented along with a full description of the experimental results.; In the analytical study, a novel unified model that predicts the non-linear flexural response of both corroded and CFRP repaired beams was developed. Implemented in the flexural model is a new bond stress-slip model that accounts for the change in the bond strength between the steel and concrete due to corrosion and/or CFRP-wrapping. Finally, a new computer program called ACFRP-04 was coded to compare the flexural model predictions with the experimental results.; General conclusions of the work along with recommendations for future studies and developments on the structural performance of corroded and CFRP repaired beams were documented. Test results showed that CFRP-repair is an effective and durable method that can be successfully used to extend the service lives of corroded reinforced concrete structures. Very good agreement between the experimental and predicted load-deflection relationships was observed. |
