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Abstract
Geosynthetic fiber reinforced soil can be used to remediate weak, near-surface soils. The purpose of this study was to determine the impact that the geofibers had on the unconfined compressive strength (UCS) of various soil types. To distinguish this work from previous studies, a larger diameter test mold was utilized to eliminate boundary effects, soils were reinforced with 12.7 mm (0.5 in) long polypropylene fibrillated fiber (PFF) inclusions, a wider range of fiber contents was tested, test specimens were carefully molded using select kaolin clay and Ottawa sand materials, and the controlled specimens were compared to the performance of four field soils. A total of 165 UCS tests were performed at both optimum moisture content (OMC) and Soaked soil conditions. In comparison to unreinforced test specimens, fiber reinforced test specimens clearly showed an increase in UCS ranging from 4% to 820% as the fiber content increased from 0.5% to 2% by mass. The data also displayed an optimum UCS, dependent upon the fine content in the soil and the percentage of fiber inclusions. As the fiber content increased, an increase in axial strain and ductility of the reinforced soil was observed due to the interaction between the soil particles and the PFFs, which also affected the failure mode of each test specimen. Specimens tested under soaked soil conditions displayed an increase in strength with increased reinforcement, but the magnitude was lower than the specimens tested at OMC conditions. The data acquired as part of this study correlated well with data presented in the literature.