| Summary: | 碩士 === 朝陽科技大學 === 營建工程系碩士班 === 101 === This research attempts to investigate the bond behavior between concrete and rebar in various sizes through the pull-out test. In addition, bond behavior between the rebar and pre-cracked concrete is also investigated. Meanwhile, the acoustic emission (AE) was employed during the test for monitoring the cracking of concrete and of a finite element analysis via ANSYS was conducted in this research. From the test results, it showed that for the same concrete strength, the ultimate pullout force increases, but the ultimate bond strength decreases as bar diameter increases. The concrete cover reduced from 10 cm to 5 cm in one side of the concrete cube made little difference in bond strength as well as the stress in rebar as de-bonding. Pre-cracked eccentric pullout concrete shows less than bond strength than those without pre-cracking. It implies that the existence of crack decay in the bond between rebar and concrete. From the finite element analysis, it showed the maximum principal stress and the maximum shear stress decreases with the increase of the ratio of cover-to-bar diameter (c/d), which consisted with the nominal bond strength observed from the test results. From a regression analysis, it showed that the deduction of bond strength for the eccentric specimen is larger than those axial as the rebar diameter increase.
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