Utilization of recycled rubber crumbs and tile powder as additives to enhance clayey soil performance

Clayey soils present challenges in engineering applications due to their inherent properties, such as low shear strength, which usually limits their use in engineering applications. Stabilization of clayey soils is crucial to enhance their performance and suitability for various purposes. Utilizing waste materials like discarded tyres and tile powder as soil stabilizers presents a sustainable solution to mitigate environmental concerns while enhancing soil properties. While previous studies have explored using either crumbled rubber or tile powder independently for soil improvement, their combined effect remained largely unexplored. This study addresses this gap by investigating the synergistic potential of blending crumbled rubber and tile powder to enhance the strength and ductility of clayey soils. A series of laboratory tests were conducted to investigate the combined effect of crumbled rubber and tile powder. First, varying percentages of crumbled rubber (2.5%, 5.0%, 7.5%, and 10%) were mixed with the soil, and standard proctor tests, California bearing ratio (CBR) tests, and unconfined compressive strength (UCS) tests were performed. Results showed optimal performance at 5.0% crumbled rubber, exhibiting the highest values for maximum dry density, CBR, and UCS. Subsequently, different percentages of tile powder (5%, 10%, 15%, and 20%) were added to the soil-rubber mixture (with 5% crumbled rubber). The addition of 15% tile powder to the 5% crumbled rubber mixture yielded the most significant improvements as maximum dry density (MDD) increased from 1.842 g/cm3 (raw soil) to 1.963 g/cm3, UCS increased from 0.5176 kg/cm2 (raw soil) to 2.606 kg/cm2, and CBR increased from 1.757% (raw soil) to 7.84%. The addition of crumbled rubber was found to shift the failure behaviour of the clayey soil from brittle to more ductile, indicating an enhanced ability to undergo deformation before failure. This study’s findings highlight the potential of combining crumbled rubber and tile powder as a sustainable solution for enhancing clayey soil properties, paving the way for further research into optimized mixture designs and expanded applications in geotechnical engineering.