Study on the protective performance of nanoscale deep penetration sealer surface treated concrete under uniaxial tension-chloride erosion coupling environment

This study examines the protective performance of Nanoscale Deep Penetration Sealer (NDPS) under coupled tensile stress and chloride erosion. An accelerated corrosion environment was created using a sustained tensile loading device combined with the Surfacing Coating Method (SCM). Experiments systematically evaluated the effects of NDPS spray volume (0, 500, 800 mL/m²) and axial tensile stress (0, 0.1, 0.3 f t , where ft represents the ultimate tensile stress of concrete) on the corrosion of plain round steel bars. Results demonstrate that the ability of NDPS to inhibit chloride ion transport and delay corrosion progression increases with higher spraying volumes. However, this protective effect attenuates with increasing stress level. Specifically, under 0.3 f t stress, the reduction in effective mass loss of steel narrows to 24.73%–39.02%, compared to 38.25%–80.23% under stress-free conditions. This indicates that the determination of spray volume under complex stress conditions must account for the interactive influences of mechanical damage. A predictive model for steel bar corrosion efficiency, developed by modifying Faraday's law through Elastic Net regression, allows for efficient assessment of NDPS protective performance under electro-accelerated corrosion. SEM analysis revealed that micro-cracks and porous regions persisted under coupled stress, accompanied by fracture of crystalline products, which collectively limited the ability of NDPS to seal dynamically evolving damage.