Experimental investigations of the bond strength between iron tailing concrete and steel bars

Fly ash, river sand, and ordinary gravel, which are used in concrete as the admixture, fine aggregate, and coarse aggregate, respectively, were replaced by iron tailing powder, sand, and gravel. The influence of the iron tailings on the bond properties between concrete and steel bar was studied by conducting pull-out tests on 16 groups and 48 specimens. At a curing age of 90 days, the splitting tensile strength of the iron tailing powder concrete (ITPC) for strength grades C25 and C30 was the lowest and was only 71.8% and 66.6% of the splitting tensile strength for the corresponding strength grade of conventional concrete (CC). The lower splitting tensile strength of ITPC caused the bond strength between the concrete and steel bar to be lower than that between the CC and steel bar, with a maximum difference of 14.67%. The bond strength between the iron tailing powder-sand concrete (ITPSC) and steel bar was slightly worse than that between the CC and steel bar, with a maximum difference of 6.88%, and better than that between the ITPC and steel bar. The bond strength between the full iron tailing concrete and steel bar was better than those between the CC and steel bar and between the ITPSC and steel bar. In addition, the bond slip characteristics were investigated.