Strength and Deformation Characteristics of Lime-Admixed Black Cotton Soil Reinforced with Sisal Fibres

Abstract

Sustainable ground improvement techniques have led to the use of natural fibres to improve the shear strength properties of soil. Lime was admixed to black cotton soil starting from 1, 2, 3, and 4%, and optimum lime content was arrived at based on maximum value of dry unit weight and corresponding water content from compaction test. Using the optimum lime content thus obtained, black cotton soil was reinforced with randomly distributed sisal fibres of average length 10–20 mm and analysed for shear strength in terms of unconfined compression test. Sisal fibres were added in varying percentages starting from 0, 0.5, 1, 2, and 3%, and compaction characteristics were assessed. Remoulded specimens were prepared to have corresponding maximum dry unit weight obtained from compaction test and were tested for unconfined compressive strength to study the effect of curing with and without lime at different periods of 0, 10, 20, and 30 days. The result indicated sisal fibre content of 0.5% and indicated maximum shear strength with and without optimum lime. The surface characteristics of sisal fibre-admixed soil along with lime using X-ray refraction and scanning electron microscopic study revealed better bonding strength between soil and sisal fibre.