Optimal Red Mud Replacement Level Evaluation in Conventional Concrete Based on Fresh and Hardened Concrete Characteristics

The global annual industrial waste production is enormous, influencing the environmental parameters affecting the whole universe. Due to rapid industrialization, cement production is increasing to meet the demand of the construction industries, harming the atmosphere and prompting scarcity of natural resources. Thus, the need for a supplementary cementitious material is essential, replacing cement either partially or completely. In the current investigation, red mud, which has some cementitious and hydraulic characteristics, is being utilized as a supplementary cementitious material and is used as a partial replacement to cement in concrete production at different percentage levels like 0% (the control concrete), 5%, 10%, 15%, 20%, and 25% with an intension to establish the optimal replacement level established on various fresh and hardened concrete characteristics. All workable mixes are subjected to physical tests (density measurement), mechanical tests (ultrasonic pulse velocity test, rebound hammer test, compressive and tensile strength test), and durability tests (acid resistance test, sulfate resistance test, and chloride resistance test). The discussions on the concrete characterization variations can be substantiated through various microstructure level tests like scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction analysis (XRD) tests. The detailed characterization tests mutually confirmed that the optimal red mud replacement level in conventional concrete is evaluated to be 15%, leading to a sustainable production evolving reasonable waste management. Graphical Abstract