Mesoscopic Characteristics on Cracks of Three-Point Bending RC Beam with Corroded Reinforcement

The RC beam usually works under the combined action of external loads and corrosion expansion pressures, and the RC beams without corrosion of reinforcements have good mechanical performance. In this study, the mesoscopic models of the three-point bending RC beams with different aggregates, different aggregate contents, and different corrosion expansion pressures were built. The plastic strain and the deflection are analyzed. The results show that the cracks of the RC beam with polygon aggregates are more dispersed than circle aggregates. As the aggregate content increases, the maximum plastic strain and maximum deflection of the RC beam decrease. The aggregate contents increased from 25% to 35%, the maximum plastic strain decreased from 3.4 × 10−3 to 2.1 × 10−3, and the maximum deflection of the lower boundary of the beam decreased from 0.005 m to 0.004 m. Furthermore, the corrosion expansion pressure makes the plastic strain increase in the concrete cover.