Bauxite residue as a binary additive in lime treated soil composites

Abstract

Industrial solid wastes have been valorized as binary and ternary admixtures in earth modification and treatment of problematic soft soils. In this investigation, an industrial waste from the aluminium industry, viz. Bauxite Residue was assessed to understand its efficacy as a binary addendum to lime in improving swelling soils. The novelty of this investigation is its focus on the combination of a scientifically established lime content viz. optimum lime content and low doses of Bauxite Residue, which seems to be virtually absent in published literature. The investigational trial explored the unconfined compression strength and stress–strain characteristics of the lime treated soil composites, treated using combinations of 7% lime and 0.25%, 0.5%, 1% and 2 % bauxite residue. The lime treated soil composites were moulded in to cylindrical specimens of 38 mm diameter and height of 76 mm, cured in air-tight polyethene covers for two hours, three, seven, fourteen and twenty-eight days and tested for their unconfined compression strength. The outcome of the investigation was also compared with some previous investigations from available literature. It was revealed that 2% bauxite residue blended lime treated soil composites was the most ideal out of all combinations studied for developing maximum strength of the lime treated soil composites. It was also noticed that bauxite residue blending of the lime treated soil composites did not affect the strength progression trends irrespective of the bauxite residue content and post peak stress–strain behaviour of the lime treated soil composites improved with increasing bauxite residue content.