Recent advances in the development of additives as corrosion inhibitors for reinforcing steel

Abstract

The corrosion of reinforcing steel poses a critical threat to the durability and sustainability of reinforced concrete infrastructure, leading to premature structural failures, high maintenance costs, and an increased environmental footprint. This comparative review analyzed, through non-parametric statistical techniques, the corrosion inhibition efficiency of synthetic and natural additives reported in scientific literature between 2020 and 2025. The results revealed that both groups achieved high average efficiencies (87.41% for synthetic and 90.87% for natural additives), with no statistically significant differences (p = 0.581). However, natural additives demonstrated greater consistency and lower variability. These findings position natural inhibitors as technically viable and environmentally friendly alternatives, aligned with circular economy strategies and service life–based design. Moreover, bio-based compounds offer advantages in terms of safety, low environmental impact, and compatibility with emerging regulatory frameworks (EPD, EN 15804, Buy Clean). Nevertheless, challenges remain regarding the standardization of testing methods, compositional variability, and long-term performance evaluation. Future research should focus on the development of intelligent hybrid additives, field validation, and life cycle assessment. This transition toward more sustainable corrosion-inhibiting technologies is key to mitigating environmental impacts and extending the service life of reinforced concrete structures.