Three recycled aggregate concrete (RAC) beam-column interior-joint specimens (including two modified recycled aggregate\nconcrete interior joints with replacement of fly ash ratio of 15%) were tested under cyclic loading in order to study the bond behavior\nof the longitudinal steel bar at RAC joint. The tests obtained load-strain hysteresis curves of longitudinal bars. The relative bond\nstrength of longitudinal bar in characteristic stages was calculated.The test results indicated that the longitudinal steel bar in RAC\njoint is able to supply a stable bond stress both in the full crack stage and in the ultimate stage, meaning that the requirements of\nstress transferring and displacement coordinating between RAC and reinforcements can be satisfied. The larger the diameter of\nsteel bar, the more serious the bond strength degradation. The RAC with fly ash can improve the interface compactness and bond\nstrength of recycled aggregate in full crack stage. When beam-column interface of concrete compression zone reaches ultimate\nstrain, the compressive stress of the longitudinal reinforcement cannot be exerted.The bond stress of the steel bar cannot realize\nthe pull and compressive stress conversion in the length of the core area of the joint owing to the stress hysteresis of the compression\nrebars.
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