Abstract
Reinforced concrete (RC) durability particularly in chloride and sulphate-rich environments is seriously compromised by corrosion. This study explores how Supplementary Cementitious Materials (SCMs) fly ash, silica fume, ground granulated blast furnace slag, and metakaolin collectively improve corrosion resistance and durability. A rigorous experimental regime, including compressive strength testing, water absorption, sorptivity, rapid chloride penetration tests, sulphate attack resistance, half-cell potential measurements, chloride diffusion assessments, and linear polarization resistance tests, was implemented. Multi-SCM mixtures significantly outperformed individual SCMs, exhibiting a 68% drop in chloride permeability, 64% less sulphate-induced expansion, and an 81% reduction in steel corrosion relative to conventional concrete. Notably, mix M13 achieved exceptional microstructural refinement and a compressive strength of 70.7 MPa 38% higher than the control alongside superior resistance to aggressive ions. However, this enhanced SCM content led to noticeable workability issues, reducing slump values by approximately 38%. Although the introduction of superplasticizers partially mitigated these drawbacks, practical implementation at a larger scale remains challenging. Further, uncertainties persist regarding long-term real-world performance, necessitating additional field validations. Ultimately, while SCM blends clearly offer substantial durability advantages, future investigations should prioritize optimizing mix proportions, addressing workability concerns, and verifying laboratory results in actual exposure conditions. This will support the advancement of sustainable, resilient RC infrastructures with enhanced corrosion resistance.