Static and Dynamic Characterisation of Red Mud Waste Material for Geotechnical Applications
摘要
Red mud waste material is a derivative spawned in the aluminium industries during the extraction of alumina from bauxite ore. Millions of tonnes of red mud are being generated and piled near the industry in India, which is increasing day by day and causing serious issues related to disposal. Accordingly, a study on red mud was executed to explore its possible utilisation in road construction and geotechnical applications. Physical and chemical characterisation were performed to examine the morphology by SEM and HRTEM while chemical constituents by FTIR and XRD and concentration of heavy metals by TCLP tests. The geotechnical characterisation, including stress–strain behaviour with fundamental properties, was carried out under static loading. Dynamic characteristics (initial shear modulus, damping ratio and resilient modulus) were also evaluated simulating with traffic loading pattern (1 Hz), by carrying out bender element and cyclic triaxial tests. It is an agglomerated structural assemblage of irregularly shaped round particles. Heavy metal concentrations were within the permissible limit and classified as non-hazardous material. It is a fine-grained material with low plasticity (Ip = 6%), high dry density (21.07 kN/m3), low permeability (5.25 × 10–7 m/sec) and low compressibility (0.045). Stress–strain behaviour is similar to other fine-grained materials with high shear strength (cohesion and angle of internal friction). The shear and resilient modulus indicated that red mud is a stiffer material, indicating minimal post-settlement of embankment. Characteristics of red mud meet the standard specifications for different geotechnical applications such as embankment/subgrade/retained fill/structural fill/levee/liner. This will lead to sustainable development.