The conversion of material density during nonlinear topologyoptimization (NTO) results in the excessive distortion of minimumdensity elements. An automatic stiffness adjustment technique is first proposed to overcome numerical instability. A multiproportional growth strategy of the minimum-density element stiffness is given according to the change of maximum strain. On this basis, a generation method of optimal load paths for corroded reinforced concrete (CRC) beams is presented by considering material properties loss and bond degradation. The design sensitivity in the form of corrosion-damaged strain energy is then derived based on the adjoint variable method. Finally, the effectiveness of the proposed method is illustrated by numerical examples. The load paths of CRC beams under various corrosion levels are studied. Results show that the proposed method can reasonably generate the load paths of CRC beams without the numerical instability.