Drained Shear Behavior of Sand Stabilized with PAYTEX-NL25 Polymer and Reinforced with Waste Tire Textile Fibers

In this paper, an environmentally-friendly liquid polymer (called PAYTEX-NL25) is used with contents of 0, 1, 2, 3, and 4% of soil weight to improve the shear strength of poorly graded sandy soil. Also, to increase the soil deformability, the modified samples were reinforced using 2% waste tire textile fibers (WTTF). The shear behavior of samples was examined by common triaxial consolidated-drained tests under 100, 200, and 400 kPa confining stresses. The results showed the high potential of modifying poorly graded sand with the mentioned polymer. Using 4% PAYTEX-NL25 polymer increases the soil's dry unit weight from 15.78 to 17.3 kN/m3 and adding 2% fiber to the soil and polymer mix declines it from 17.3 to 16.6 kN/m3. The sand modified with 4% polymer showed cohesion and internal friction angle of 1280 kPa (more than 36 times pure sand) and 44 degrees (1.13 times pure sand), respectively. The main negative point of the sand modified with the mentioned polymer is its brittle behavior, which was improved through reinforcement with WTTF. However, in high polymer content (more than 2%), the effect of WTTF is greatly reduced.