Investigation of the shear behavior of EPS geofoam

ABSTRACT: Expanded polystyrene (EPS) geofoam has been used in a wide range of geotechnical applications since 1960s. These applications involve the use of geofoam either as a lightweight fill material (e.g. in embankments and bridge approaches) or as a compressible inclusion (e.g. in retaining walls and culverts). In these applications, geofoam is placed directly in contact with other construction materials. Therefore, for successful analysis and design of these composite structures, a detailed knowledge of both compression and shear behavior of the geofoam material as well as the strength of the interface are needed. In the present research, an attempt has been made to determine the shear strength parameters of geofoam monoblocks and the interface strength properties of EPS blocks in contact with other construction materials using direct shear tests (DSTs). Test results showed that both the geofoam density and the applied level of normal stress have significant effects on the shear strength of monoblock as well as the interface properties of EPS geofoam.