Stabilization of clay soils exposed to freeze-thaw conditions with waste Kevlar

In recent years, the use of waste materials for soil stabilization has gained attention due to their environmental and economic advantages. Kevlar, a synthetic, high-strength fiber commonly used in telecommunications, becomes a significant source of industrial waste at the end of its service life. In this study, the potential utilization of waste Kevlar material for improving clay soils against freeze-thaw effects was investigated using computed tomography (CT) and scanning electron microscopy (SEM) imaging techniques. For this purpose, waste Kevlar was randomly mixed into two types of clay soils (CL and CH) at different dosages (0.05%, 0.25%, 0.5% and 1%) and fixed fiber length of 10 mm. The prepared samples were subjected to 2, 5, and 10 freeze-thaw cycles, after which their stress-strain behavior, peak stress values, and freeze-thaw resistance were evaluated. The experimental results indicated that the peak stresses increased in all cycles with the increasing of waste Kevlar content. Compared to the unreinforced soil, in CH clay reinforced with 1% Kevlar, peak stresses increased by approximately 23%, 26%, 59%, and 45% for 0, 2, 5, and 10 cycles, respectively. In the case of CL clay, the corresponding increases were approximately 76%, 43%, 49%, and 44%. These findings demonstrate the feasibility and sustainability of utilizing waste Kevlar as an effective reinforcement material to enhance the durability of clay soils against freeze-thaw conditions in geotechnical engineering applications.