3.2 Lightweight and Structural Fills A method that allows construction of relatively light structures on very soft base soil is to use either a lightweight fill or a carefully placed structural fill onto which the foundation is placed. Lightweight fills may use expanded shale, certain industrial slags,and fly ash.These 淘 materials may be mixed with sand and/or gravel to produce a fill of the desired density and durability. EPS (expanded polystyrenc)fill can be used for embankment in highway engineering. 超 3.2 Lightweight and Structural Fills ▪ A method that allows construction of relatively light structures on very soft base soil is to use either a lightweight fill or a carefully placed structural fill onto which the foundation is placed. ▪ Lightweight fills may use expanded shale, certain industrial slags, and fly ash. These materials may be mixed with sand and/or gravel to produce a fill of the desired density and durability. ▪ EPS (expanded polystyrenc) fill can be used for embankment in highway engineering