Bond behavior of steel reinforcement in concrete containing ferronickel slag and blast furnace slag powder

Abstract Thirty-six pullout tests, including twelve groups of three specimens, were performed to study the bond behavior of steel reinforcement in concrete containing ferronickel slag and blast furnace slag powder (F-S powder/concrete). Test parameters considered in this research were F-S powder replacement percentages (i.e., 0%, 10%, 20%, 30%, 40%, and 50%) and concrete strength grades (i.e., C30 and C35). Unexpectedly, the results showed that the bond quality of steel reinforcement in F-S concrete was inferior to that of normal concrete even with comparable concrete strength. The more F-S powder content, the greater the inferiority. Through investigating the underlying mechanism, it was found that bleeding adversely affected the reinforcement-concrete bond quality in F-S concrete. Based on the pullout test results, a bond stress-slip relationship and an anchorage length modifying factor were proposed for F-S concrete of C30 and C35 strength grade. The conclusions would help designers assess the suitability of a particular F-S concrete for use in a given structure.