Bond Stress Distribution and Bond–Slip Model of Deformed Steel Bars in Iron Tailing Sand Recycled Aggregate Concrete

Abstract

In this study, the bond stress distribution and bond–slip model of steel bars and iron tailing sand recycled aggregate concrete (ITRAC) were investigated using central pullout tests on 33 steel bars and ITRAC bonded specimens. The results show three failure modes for the bonded specimens: splitting, pullout, and splitting–pullout. Compared with the maximum bond strength of nature sand concrete (NAC), the maximum bond strength of the iron tailing concrete and ITRAC specimens increased by 23.12% and 6.08–23.96%, respectively. After adding 1% steel fiber, the maximum and residual bond strengths of ITRAC increased by 40.82% and 129.10%, respectively, compared with those of NAC. The maximum bond strength of ITRAC decreased after the configuration of the stirrups. The bond stress distribution characteristics of the ITRAC specimens resembled those of recycled aggregate concrete (RAC). Generally, two bond stress peaks emerged, and the uniformity of the bond stress distribution improved after adding RAC to the iron tailing sand (ITS). The results of the proposed ITRAC bond–slip constitutive model agreed with the test results.