High-strength self-compacting concrete incorporating red mud: Development and comprehensive performance evaluation

In this paper, red mud (RM), a highly alkaline waste material from aluminum production rich in alumina, iron, and silica, is used as a supplementary cementing material in developing high-strength self-compacting concrete (HS-SCC). The resulting fresh and hardened-state properties were determined. RM was added to HS-SCC in varying amounts to replace the cement. The results indicate that replacing cement with RM enhances the cohesiveness and flowability of SCC with improved mechanical and durability properties, due to its finer gradation and pozzolanic activity. The in-depth microstructural analysis by SEM showed enhanced packing density, densified pore structure, and interfacial strengthening. The optimal dosage of RM was determined as 10%, leading to the 28-day compressive strength of the developed SCC >57 MPa. The RM replacement at 30% also significantly improved resistance against acid attack and water penetration, while the corresponding drying shrinkage was lower with improved stress-strain behavior. The enhanced properties are primarily due to greater strength and elastic modulus. These findings highlight the use of RM as a viable, sustainable cement substitute that can help resource conservation and environmental remediation in producing high-strength, high-performance self-compacting concrete.