Hawileh, RamiAttom, MousaKhalil, Ahmed Mohsen2024-09-302024-09-302024-0629.330-2024.01https://hdl.handle.net/11073/25642A Doctor of Philosophy Dissertation in Materials Science and Engineering by Ahmed Mohsen Khalil entitled, “Assessment of bent and straight GFRP reinforcement conditioned in harsh environments”, submitted in June 2024. Dissertation advisor is Dr. Rami Hawileh and dissertation co-advisor is Dr. Mousa Attom. Soft copy is available (Dissertation, Completion Certificate, Approval Signatures, and AUS Archives Consent Form).This dissertation investigated the impact of durability on the strength of bent and straight GFRP rebars in harsh environments. The typical tensile strength observed in bent FRP rebars compared to the strength of straight rebars was on average lower by 40%, unlike conventional steel. There was a lack of studies on the durability of bent FRP bars in harsh environments like those in the UAE and Gulf region. To address this gap, two sets of durability tests were conducted, one indoors and another outdoors, with a specific focus on performance in saline environments. A comparative analysis was conducted among the results of control unconditioned samples, those exposed to the outdoor saline environment of the UAE, and those subjected to indoor accelerated durability setups in the laboratory. The aim was to identify any consistent patterns of strength deterioration in straight and bent GFRP rebars across these two testing setups (indoor and outdoor), as compared to control unconditioned specimens. The variables of the experimental program were GFRP rebar diameter, manufacturer, rebar shape, radius of curvature, durability setup, and aging duration. The results covered failure modes, load-deflection responses, strain measurements, tensile strength retention, and microstructure analysis of the GFRP rebars. Test results showed that GFRP rebars, whether straight or bent, demonstrated similar initial stiffness. However, load capacity and deflection variations were observed based on rebar size and exposure conditions. The microstructure analysis through SEM showed that the manufacturing bending process changed the cross-section of GFRP rebars from circular to approximately rectangular, which altered the load distribution and induced differential stresses along the rebar length. Additionally, environmental exposures caused notable fiber and fiber-matrix interface damage in the GFRP rebars. This study concluded that there was moderate retention of tensile strength, with an average of about 80% for the outdoor setup and 75% for the indoor accelerated setup over the exposure periods. Thus, nonmetallic GFRP reinforcement was a viable alternative to steel reinforcement in RC structures exposed to marine and harsh saline environments.en-USDurabilityOffshore StructuresMarine EnvironmentAccelerated DurabilityMicrostructureRadius of CurvatureRetentionTensile and Bent FRPDissertation