The Effects of Fiber Amendment on the Surface Crack Evolution on Clayey Soil under Freeze-Thaw Cycles

Due to the recent rapid environmental changes, there are significant changes in frozen soils, permafrost, and seasonally frozen ground. The seasonal temperature fluctuation-induced freeze-thaw (F-T) cycles significantly influence geotechnical infrastructure and especially impact the pavement foundation due to deterioration of pavement quality and imposed slope instability. Recent studies have confirmed that the application of fiber- reinforced soil is successful in the desiccation and wetting-drying cycles related to clayey soil cracking. However, different types and content of fiber impacts on surface cracking phenomena of clayey soil under the freeze-thaw cycle behavior have not been studied. Therefore, this study focuses on the influence of different types of fibers (i.e., carbon, glass, and basalt) and fiber content (i.e., 0%, 0.05%, 0.1%, and 0.15%) on surface cracking under freeze-thaw cycles on clayey soils. Each freezing and thawing process is continued for 12 h and controlled at temperatures of -20 degrees C and 20 degrees C, respectively, and the whole experiment consisted of five freeze-thaw cycles. The 2D image processing techniques and water evaporation characteristics were utilized to capture the crack evolution and propagation under the freeze-thaw cycle process. Results show that with an increased dosage of any type of fiber for the freeze-thaw samples, the crack area, total crack length, fractal dimension, and average crack width decrease. Further results showed that based on selected fiber types, carbon had the best performances; this might be with respect to the smaller specific gravity-related higher number of fiber particles used for the treatment and its higher tensile strength. In terms of basalt and glass, the quantification results for cracks were fairly similar, while their specific gravity and tensile strength values also hold close resemblances.