In this study, the bond behavior of corroded reinforced concrete was investigated by conducting pull‐out tests on concrete specimens with variable induced crack widths and different splitting modes. To simulate cracks due to corrosion and focus on their effect on bond strength degradation, a novel method using expansion agent filled pipes is proposed. With the increase of the crack width over elapsed time from filling the aluminum pipe with an expansion agent, a target crack width was obtained. The results confirm that the type of splitting greatly influences the reduction in bond strength with deterioration of bond strength more severe in “Side‐split” than in “Single‐split.” Furthermore, using the surface crack width as a variable, empirical formulas to predict bond strength degradation due to corrosion of rebar are proposed. These prediction models give a good correlation when compared to the available literature.