Probing into the fundamental effect of Cr on the failure mechanisms of rebars within carbonation and stress environments

The corrosion behavior and failure mechanism of Cr-modified HRB400 under carbonation and constant load in simulated offshore environment was comprehensively investigated. Results indicate that Cr modification reduced the corrosion current density from 6.25 μA/cm² to 4.55 μA/cm² and altered the rust layer, which initially impedes chloride ion diffusion at the early-stage corrosion. Statistics of the corrosion pits reveal the synergistic effect of carbonation and constant load intensifies localized corrosion, fostering crack nucleation and propagation. The enrichment of Cr in rust layer effectively reduces the crack propagation in the early stage of corrosion, but the stress will reduce the protection of Cr in the rust layer. This study provides novel insights into the influence of multiple environmental factors on the corrosion behavior of HRB400 and elucidates the mechanisms by which Cr modulates corrosion resistance under harsh conditions, offering valuable design guidance for enhancing anti-corrosion performance of reinforced structure under load during long-term service.