The global production of PET (Polyethylene Terephthalate) has been increasing in the last 50 years, however, in the last 10 years the production of plastic has increased exponentially, making the reuse of this material a worldwide challenge. This article presents the analysis of the mechanical properties of silty sand with the addition of recycled PET in percentages of 1%, 2%, 3%, 4% and 5%; for this, Granulometry, Atterberg limit, specific gravity, modified proctor and shear direct tests were performed in order to analyze the behavior of the mentioned mixtures. Experimental results showed an increase in shear strength with the addition of 3% PET.