Investigation of the effect of the reinforcement length on freeze-thaw behavior in fine grained soil randomly reinforced with discrete synthetic fibers

The purpose of this study was to investigate the effect of reinforcement length on freeze-thaw behavior in fine-grained soils randomly reinforced with polypropylene fibers. Polypropylene fibers at different lengths (3mm,6mm, and l2mm) were used as reinforcement. High Plasticity clay soil (CH) and Low Plasticity clay soil (CL), respectively, obtained from the clay reserves in Erzurum - Oltu and Erzurum - Çat regions were used as fine-grained soil. For each polypropylene fiber length, samples wilh optimum water content were prepared by adding polypropylene fiber into the soil at the ratios of 0.15%, 0.20%, and 0.25% of the total dry clay soil weight. A series of freze-thaw and unconfined compression tests were carried out in the laboratory with the obtained samples. The freeze-thaw tests were repeated for 1,3,5, and 10 different cycles. The samples were subjected to unconfined compression tests before and after each freeze-thaw cycle, and the stress deformation diagrams of the samples were obtained. The experiments revealed that with an increase in the freze-thaw cycle number, the unconfined compression strength decreased. In addition, it was observed that increase in the fiber length of the reinforced samples that were subjected to freeze-thaw cycles, exerted a negative effect on the unconfined compression strength.