Stabilization of an expansive soil using phosphogypsum

Özkan, İlyas
Expansive soils are a worldwide problem that poses several challenges for civil engineers. Such soils swell when given an access to water and shrink when they dry out. The most common and economical method for stabilizing these soils is using admixtures that prevent volume changes. Studies for treatment of expansive soils with phosphogypsum are very limited in literature. In this study the effect of phosphogypsum (PG) in reducing the swelling potential is examined. The expansive soil was prepared in the laboratory by mixing kaolinite and bentonite. Recycled PG was added to the soil at 5 to 25 percent by weight. Grain size distribution, Atterberg limits and swell percent were determined. Using PG improved the performance of the expansive soil by reducing the swelling potential. The addition of more than 15% phsophogypsum did not affect the swelling potential. Therefore, the optimum phosphogypsum content was found as 15%. Additionally, phosphogypsum was used with lime and ground granulated blast furnace slag (GGBFS). The addition of %15 PG and %15 GGBFS decrease the swelling potential vi from % 43.16 to % 9.16. When the curing period for sample including PG and GGBFS increase, the swelling potential for this sample declined.
Citation Formats
İ. Özkan, “Stabilization of an expansive soil using phosphogypsum,” M.S. - Master of Science, Middle East Technical University, 2015.