Strength of Silty Soil Treated with Cement and Reinforced with Plastic Water Bottles Waste

The silty soil is subject to significant settlement and a decrease in bearing capacity when subjected to high stresses. Improving the properties of this soil is necessary to achieve the bearing capacity required by buildings. In this study, various percentages of plastic water bottle waste fibers (PET) and cement were used. The effect of these materials on the unconfined compressive strength (UCS), indirect tensile strength (ITS), and punching tensile strength (PTS) of the silty soil was studied. All cemented soil samples were cured for (7, 14, and 28) days at 25 °C. The results of laboratory tests showed that the use of PET fibers in percentages (0.5, 1, and 1.5%) led to an increase in the UCS and the ITS at each percentage. These resistances reached their maximum value at (1%) fiber content and (30) mm length. The use of (1%) PET fibers and (30) mm length with (4%) cement and (28) days as a curing time increased these resistances to 2626 and 7693%, respectively. The PTS of soil reinforced with PET fibers in percentages (0.5, 1, 1.5, and 2%) increased at each percentage. The value of the increase was about 229 % at 1.5 % with a length of (30) mm of fibers, while its value was about 4732 % at 1.5 % of PET and 4 % cement and for a curing time of (28) days compared to soil without additions, i.e., 12kN/m2.