Theimportance of an accurate simulation of service conditions in the bond performance of reinforced concrete structures in coastal\nregions is highlighted. Four widths of initial crack of 0, 80, 150, and 210 microns were artificially made by inserting slice into bond\nspecimens during concrete casting. Three bar diameters of 10 mm, 14 mm, and 18mmwere selected. At 28 days, the bond specimens\nwere exposed to the environment of wet-dry cycles of seawater and atmosphere for another 90 days. The pull-out test was then\nconducted and chloride contents were tested at crack area along 40mm depth. Results show that, for the specimen with 10mm\nbar diameter, cracks width of less than 80 microns vanished rapidly during wet-dry cycles; for other specimens, cracks width of\n100ââ?¬â??150 microns decreased slightly. However the cracks of width more than 200 microns increased gradually; the chloride content\ndecreased along the depth of concrete, and the chloride content increased as the widths of initial cracks increased or as the bar\ndiameters increased.The ductility of bond specimens decreased as the diameter increased.
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