In the last decade, ground improvement by using polypropylene fibers has gained popularity. In this study, different sets of specimens were constituted according to the fiber ratios and unconfined compressive testing was applied to the fiber reinforced cement admixed sand specimens to evaluate their strength development. Lightly cemented sand specimens were prepared by adding 2, 4, and 6% of cement to the dry soil. The fibers used in this study had a length of 6 mm and added to the soils in percentages of 0, 0.3, 0.6, and 0.9. The results of this study indicated that fiber addition to the cemented sand improved the unconfined compressive strength of the medium. It was seen that both cement ratio and fiber ratio must be considered as separate components of the mixture. Although the specimens that had 2% cement ratio and %0.9 fiber ratio combinations resulted in the highest values of unconfined compressive strength in its experimental set, the highest values of unconfined compressive strength was obtained for the specimens with 4% and 6% cement ratios which had 0.6% of fibers. Freeze-thaw tests were applied in a conventional manner, therefore the freezing period lasted one day and thawing period was the next day, each cycle completed in two days. Number of cycles was 0, 1 and 3. Increment of cycles resulted in the strength loss of the specimens, but the loss of strength was partially prevented by using fiber reinforcement confirming that fiber reinforcement may provide a good solution for soils under freeze-thaw effects.
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