Effects of Loading Conditions and Stirrup Arrangement on Corrosion-Induced Expansion Strain and Cracking in Reinforced Concrete Beams

To investigate the effects of loading type and stirrup arrangement on the corrosion and deterioration characteristics of reinforced concrete beams, constant current accelerated corrosion tests were conducted under no load, uniaxial compressive load, and biaxial compressive load conditions, with specimens without stirrups serving as the control group. A comparative analysis was performed on the overall corrosion of the top surface of the concrete beams, the expansion strain of the concrete beams, and the crack distribution on the top surface of the beams with and without stirrups. The characteristics of the protective layer spalling in the concrete beams under different loading conditions were also discussed. The results showed that the expansion strain of specimens with normal stirrups was significantly higher than that of specimens without stirrups. Under uniaxial compressive loading, the expansion strain was lower compared to the no-load specimens. Under biaxial loading at 15% of the compressive strength, the expansion strain was minimal, suggesting that the loading compaction effect suppressed crack propagation. Furthermore, under biaxial loading, as the load level increased, the Poisson effect intensified the tensile deformation in the vertical direction, causing cracks to propagate rapidly. The extent and depth of the spalling of the protective layer increased significantly, exhibiting more severe deterioration characteristics.