The effect of steel fiber on the bond between concrete and deformed steel bar in SFRCs

In this study, the effect of steel fiber amount and concrete cover on concrete deformed steel bar bond of steel fiber concretes (SFRCs) has been investigated. Steel fibers with l/d ratios of 60 and 80 were added to the concretes designed in C20, C40 and C60 classes in 10, 20, 30, 40, 60 and 80 kg/m3 amounts. S420 deformed steel bars with 14 mm diameter were embedded at 70 mm bond length to cubic specimens prepared from the concretes produced with and without steel fiber enabling the concrete cover to be 40, 55 and 70 mm. The specimens were subjected to pullout test. Moreover, 28-day mechanical tests of the concretes produced were defined.As a result of the studies conducted, the pullout loads are found to increase by 7–16% when the amount of steel fibers and aspect ratio in the SFRCs produced increase when compared to concretes without steel fiber. In addition, the concrete reinforcement bond was mathematically modeled using 28-day mechanical properties of the concretes and the concrete covers.

► The concrete–reinforcement bond was increased with the increase in concrete cover thickness.
► Presence of steel fibers, the concrete–reinforcement bond increased.
► The concrete–reinforcement bond was raised with the increase in mechanical properties of SFRCs.