Bond between high strength concrete with recycled coarse aggregate and reinforcing bars

Bond Behaviors Between Full-Recycled-Aggregate Concrete and Deformed Steel-Bar

“…This presents a better bond property of deformed steel bar to aRAC, due to the enhancement of the secondary hydration of cement grains composited in fine RCA on the interface between deformed steel bar and aRAC [20,21]. Similar test results have been reported for the bond strength between deformed steel bar and RAC [26,31]. Based on the study of bond-slip relationship between deformed steel bar and manufactured sand concrete [46], the bond-slip relationship of deformed steel bar to aRAC can be calculated by least squares approach, and expressed as the composition of micro-slip, slip, internal splitting-broken and decline segments, where, f t is the tensile strength of aRAC, α sr is the influencing coefficient of RCA, and all other terms are as previously described.…”

“…The pull-out test, beam-end test and beam bond test were applied. Due to the multi-actions on the interface of steel bar and RAC, failures of specimens took place as the pull-out of steel bar [27,28], splitting of concrete [27 -32] or yield of steel bar [30,31]. Such multi-actions were affected by the RAC strength, the RAC depth covering steel bar and the bond length and type of steel bar.…”

“…If the bond strength was normalized as the ratio to the compressive strength, square root of compressive strength or tensile strength of RAC, it was only slightly affected by the content of RCA and no less than that of referenced ordinary concrete [28, 33 -37], even increased with the increasing content of RCA [32,33,35]. Meanwhile, when the mix proportion of RAC was adjusted properly to get an equal compressive strength with referenced ordinary concrete, the bond behavior was similar and the bond strength was not influenced by the content of RCA [38 -40], even a higher normalized bond strength reached with the increased content of RCA [26,31]. From a general view, the bond strength between steel bar and RAC was reliable compared with the referenced ordinary concrete under the same conditions.…”