Sand Reinforced with Recycled Cotton Textiles from Waste Blue-Jeans: Stress-Strain Response

The resilience and sustainability of infrastructure can be increased by reducing quantities of natural materials used in construction and/or relax the requirements for their properties. To foster sustainable solutions and circular economy, the potential of using wastes and by-products from different industries as reinforcements should be explored. Herein the stress-strain response of a sand reinforced with waste cotton textile from blue-Jeans was studied using conventional triaxial tests. The responses observed were compared to the unreinforced soil and analysed using a critical state framework. The reinforcements were cut from waste cotton blue-Jeans, without any treatment, in three forms: horizontal discs, and discrete fibres with two different dimensions. The waste cotton textile from blue-Jeans performed well as reinforcement elements within sand. In general, the different forms of reinforcement studied (horizontal disc and fibres) placed at mid-height of the triaxial test specimens were able to improve the stress-strain response of the reinforced soil, relative to the unreinforced soil. The reinforcements increased the ductility of the stress-strain response, increased the strength parameters (for both peak and large strain responses), and increased the critical state parameters. The different forms of reinforcement are mobilised differently. For the loading conditions of the conventional compression triaxial tests, the horizontal disc of reinforcement was the most effective.