Effect of Phosphogypsum As a Waste Material in Soil Stabilization of Pavement Layers

The aim of this research is to use phosphogypsum (PG) waste produced from phosphoric acid plants as a stabilization material to improve the properties of non-plastic soil, such as Aqaba soil in Jordan. The mixture formula of the material was optimized and the PG dosages 0%, 5%, 10%, 20% and 25% by weight of the soil sample were tested. The sieving and grading of the soil, Atterberg limit, dry unit weight, moisture content, Proctor and Califorina Bearing Ratio (CBR) were tested. It was concluded that 21% represented the optimum percentage of PG in all soil specimens, especially in Proctor and CBR tests for the red silty sand and gravel (A-2-4). This result also could influence the base, sub-base and sub-grade pavement layers to one pavement layer with less depth of its stabilization.