Evaluation of the Effect of Initial Moisture Content of Sandy Subgrade and Emulsion Bitumen Percentage on Final Deformation and Strength of Fiber and Cement-Reinforced Pavement

Construction of roads and development projects on sandy soils is usually done due to lack of adequate strength to the displacement of subgrade soil or redirecting. Therefore, stabilization and investigation of the factors affecting its strengthening with different materials have always been of interest to the researchers. Studies have shown that the use of polypropylene fibers generally increases the ductility and mechanical strength, such as compressive strength and shear strength, of soils. On the other hand, the initial moisture content plays an important role in stabilizing with emulsion bitumen. Therefore, in this study, the stabilization and improvement of dune sand, using different initial moisture contents, emulsion asphalt binder, and fiber in optimum cement percent were considered. Uniaxial compressive test results showed that addition of fiber increases the bearing capacity by an average of 10%. Increasing the initial moisture content increased the strength performance of the sand subgrade and then decreased in high moisture contents. Also, increasing the percentage of emulsion asphalt binder and fiber had a significant impact on the enhancement of stabilized subgrade ductility.