Evaluation of Geofoam as a Geotechnical Construction Material.

Geofoam has the scientific name of expanded polystyrene (EPS). A block of EPS is made from particles of polystyrene through an expanding and melting process in an automatic mold machine by adding steam. The geofoam construction method employs large EPS blocks with unit weights between 12 and 30 kgforce/m3. In the 1970s, the use of EPS as a lightweight embankment in highway and earthwork developed concurrently in the United States and Norway. Most notably, in 1972, the Norwegian Road Research Laboratory placed geofoam in the approach fill of the Flom Bridge. The advantages of this construction method are that geofoam can be used not only to replace ground fill material but also to reduce the load applied to the foundation. This paper will introduce the following topics related to geofoam: the background and inspection conditions in Taiwan, United States, and Japan, the quality investigation of EPS production, and the experimental and analysis results of EPS manufacturing quality and homogenous test. This research illustrated that the quality control chart can analyze the stability of manufactured EPS. Meanwhile, the homogeneous testing method, which is put forth in this paper, can actually examine the stability of EPS manufacturing procedure. The results of this study can be used as the reference for quality control of geofoam. The issue of geofoam used for collision prevention, self-weight decreasing, and landslide resistance in geotechnical engineering will also be discussed. [ABSTRACT FROM AUTHOR]