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Abstrakt:
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Bond degradation due to rebar corrosion and fatigue loading may affect the serviceability and even safety of
reinforced concrete (RC) bridges. 15 specimens confined with stirrups were cast for eccentric pull-out tests,
and 12 of them were corroded with the target mass loss of 0.03 by the impressed current method. Monotonic
pull-out tests were conducted on three corroded and three uncorroded specimens. Wavy descending branch
was found in bond stress-slip test curves of uncorroded specimens attributed to stirrup confinement, however
it disappeared in those curves of the corroded specimens due to the corrosion loss of rebar transverse ribs.
Based on the tested monotonic bond strength, the other nine corroded specimens of different fatigue
damages were obtained through repeated loading with different levels and cycles before undergoing
monotonic pull-out tests. It is observed that the relative slip increases with a gradually decreasing rate as the
loading cycles increase. The monotonic tests of specimens with fatigue damage show that the bond strength
increases to a certain value and then decreases with the increase of fatigue loading cycles. Moreover, the
higher the loading level is, the fewer cycles are needed to reach the maximum bond strength. In addition, the
peak slip corresponding to bond strength decreases with the increase of fatigue loading cycles.
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