Enhanced stabilization of weak materials derived from highly weathered slate rock under harsh climatic conditions

Abstract

Extensive research in the field of soil improvement has led to significant advancements, many of which offer environmentally friendly solutions. The performance of these solutions in practical applications is particularly crucial, as their durability under local climatic conditions determines their overall effectiveness. In this study, to evaluate the mechanical and microstructural behavior of stabilized soils under wet-dry and freeze–thaw cycles, weak subbase materials derived from the chemical weathering of slate were stabilized and reinforced using an environmentally friendly approach incorporating lime, nano-zeolite, and polypropylene fibers. The optimal composition was then subjected to severe climatic conditions, including multiple wet-dry and freeze–thaw cycles, and its mechanical behavior was evaluated in terms of maximum strain energy, secant modulus, residual stress, and brittleness along with its microstructural characteristics was thoroughly examined. The results indicate that the stabilized 12LZPP specimen (containing 7.8% lime, 4.2% nano-zeolite, and 1% fiber), after enduring climatic conditions, retained the minimum acceptable subbase criterion and more than 91% of the absorbed energy. Additionally, the residual stress at 10% strain remained above 120% of the initial soil. Scanning electron microscopy (SEM) images and X-ray diffraction (XRD) patterns corroborated the mechanical and chemical analysis results. Finally, the effectiveness of this method was comprehensively validated in terms of mechanical, microstructural, and environmental aspects.