We report the experimental study on the behavior of a reinforced sandy soil and not reinforced with coir fibers, by conducting physical and mechanical tests (isotropic drained triaxial tests). Coir used was cut in lengths of 25 and 50 mm, knowing that its diameter is not constant, because it is a natural fiber. The aim is to establish behavior patterns that might explain the influence of the addition of coir fibers, relating it to the shear strength parameters and deformation of sandy soil. The tests were performed on specimens compressed in relative density of 50 percent and 10 percent moisture, varying fiber contents in the proportion of 0.25; 0.50; and 0.75 percent on the dry weight of the soil. It was found that the presence of the fiber does not change the physical properties of pure sand. With regard to mechanical behavior proved the existence of an increase in shear strength in all soil-fiber mixtures, since it was observed a significant increased cohesive intercept of mixtures, and a modest increase in friction angle, compared to the results obtained for the pure sand. The fibers of the mixture showed the best strength results were subjected to a sealing process with the aim of increasing the useful life of the composite, where the strength parameters have not changed compared to the mixture without sealing fibers.The results were satisfactory for use in sand-fiber landfill layers and embankments on soft soils, thus giving a more sustainable destination to this waste, ensuring temporary and more economical solutions.