Stabilization of Expansive Soil using Leather Industry Waste Ash

Abstract

Expansive clays are one of the most widely found soil types across the globe, known for their low strength and high swelling behavior. Numerous studies have been conducted in the past few decades to stabilize such soils using various additives. The traditional stabilizers, such as cement and lime, not only prove to be quite costly due to their high industrial demands but also result in the exhaustion of available natural resources. newline The current study is a novel effort based on the distinct addition of two different wastes originating from the leather industry in ash form, namely limed leather waste ash and blue leather waste ash. These can be utilized as potential stabilizers to enhance soil strength and reduce the swell-shrink characteristics of expansive clays. The effects of the waste ashes on the properties of expansive soil are analyzed at both macro and micro levels. newline The macro-level studies are based on the characterization of the chemical nature of the waste ashes and their effects on the consistency, mechanical properties, and swelling properties of the soil in uncured and cured states, with an observation period of up to 28 days. Meanwhile, the micro-level studies aim to examine the changes in surface structure, particle bonding, and chemical nature of the soil at the microscopic level with increased contact period with the stabilizers in the presence of moisture. newline The study also involves the refinement of the blue leather waste ash through the use of a secondary stabilizer called microfine slag, to optimize its use in the stabilization of expansive soil. The optimum contents of the waste stabilizers are determined based on their most desirable effects on the properties of expansive soil. newline A one-dimensional rainfall simulated leachate study has been carried out over a pavement model stabilized with leather waste ashes in crude and refined form, to evaluate the possible impact of ash treatment on the water table. It is found from the study that the waste, when used in ash