# Analysis of Mechanical Properties of Crumb Rubber Tires Mixed with Silty Sand of Various Sizes and Percentages

## TL;DR

This study shows that mixing crumb rubber from old tires with silty sand improves its mechanical strength and offers a sustainable way to recycle tire waste.

## Contribution

The study introduces a novel approach to enhance silty sand's mechanical properties using crumb rubber of different sizes and percentages.

## Key findings

- Adding crumb rubber increased deviatoric and shear stresses, especially with 5–10 mm particles at 3–9% content.
- The stiffness modulus decreased significantly in mixtures with 6% crumb rubber.
- The method offers a sustainable solution for tire recycling and silty sand stabilization in construction.

## Abstract

Every year, a billion tires are discarded worldwide, with only a small percentage being recycled. This leads to significant environmental hazards, such as fire risks and improper disposal. Silty sand also presents technical challenges due to its poor shear strength, susceptibility to erosion, and low permeability. This study explores the incorporation of crumb rubber derived from waste tires into silty sand to enhance its mechanical properties. Crumb rubber particles of varying sizes (3–6 mm, 5–10 mm, and 10–20 mm) were mixed with silty sand at 0%, 3%, 6%, and 9% percentages, respectively. Triaxial compression tests of unconsolidated and consolidated undrained tests with cell pressures of 100, 300, and 500 kPa were conducted. The deviatoric stress, shear stress, and stiffness modulus were investigated. The results revealed that the addition of crumb rubber significantly increased the deviatoric and shear stresses, especially at particle sizes of 5–10 mm, with contents of 3%, 6%, and 9%. Additionally, the stiffness modulus was notably reduced in the mixture containing 6% crumb rubber tire. These findings suggest that incorporating crumb rubber tires into silty sand not only improves silty sand performance but also offers an environmentally sustainable approach to tire waste recycling, making it a viable strategy for silty sand stabilization in construction and geotechnical engineering performance.