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Geofoam is expanded polystyrene (EPS) or extruded polystyrene (XPS) manufactured into large lightweight blocks. The blocks vary in size but are often 2 m x 0.75 m x 0.75 m. The primary function of geofoam is to provide a lightweight void fill below a highway, bridge approach, embankment or parking lot. EPS Geofoam minimizes settlement on underground utilities. Geofoam is also used in much broader applications, including lightweight fill, green roof fill, compressible inclusions, thermal insulation, and (when appropriately formed) drainage.〔Koerner, R. M. (2012), ''Designing With Geosynthetics'', 6th Edition, Xlibris Publishing Co., 914 pgs.〕 Geofoam shares principles with geocombs (previously called ultralight cellular structures) which has been defined as "any manufactured material created by an extrusion process that results in a final product that consists of numerous open-ended tubes that are glued, bonded, fused or otherwise bundled together." The cross-sectional geometry of an individual tube typically has a simple geometric shape (circle, ellipse, hexagon, octagon, etc.) and is on the order of 25mm across. The overall cross-section of the assemblage of bundled tubes resembles a honeycomb that gives it its name. Presently, only rigid polymers (polypropylene and PVC) have been used as geocomb material. ==History== The first use of EPS Geofoam was in Oslo, Norway in 1972. Geofoam was used in the embankments around the Flom Bridge in an effort to reduce settlements. Prior to installing geofoam, this area experienced 20–30 centimeters of settlement annually causing extreme roadway damage.〔Elragi, Ahmed Fouad. "Selected Engineering Properties and Applications of EPS Geofoam - Introduction." Softoria Group. 2006. Web. 18 Nov. 2010. Due to the success of the Oslo geofoam project, the first International Geofoam Conference was held in Oslo, Norway in 1985 for engineers to exchange knowledge, research results, share new applications, and discuss case histories. Since then, two more conferences were held in Tokyo, Japan and Salt Lake City, US, in 1996 and 2001, respectively. The most recent conference was held in June 2011 in Lillestrom, Norway.〔Norwegian Public Roads Administration, and Tekna. "4th International Conference on Geofoam Blocks in Construction Applications." Tekna. Norwegian Public Roads Administration. Web. 18 Nov. 2010. Between 1985 and 1987, Japan used over 1.3 million cubic meters of geofoam in 2,000 projects. Testing and use of geofoam in these projects demonstrated the potential advantages of geofoam as a lightweight fill. For example, Geofoam was placed beneath runways in Japanese airports, proving the material can sustain heavy and repeated pressure.〔 Geofoam was first used in the United States in 1989 on Highway 160 between Durango and Mancos, Colorado. An increase in rainfall caused a landslide, destroying part of the highway. Geofoam was used to create highway side slope stabilization to prevent any similar issues. The use of geofoam in this project versus conventional restoration resulted in a cost savings of 500%.〔Geofoam Research Center. Syracuse University Syracuse, 2000. Web. 18 Nov. 2010. The largest geofoam project in the United States took place from 1997 to 2001 on Interstate 15 in Salt Lake City, Utah. Geofoam was chosen to minimize that amount of utilities that would need to be relocated or remodeled for the project. A total of 3.53 million cubic feet of geofoam was used, and approximately $450,000 was saved by eliminating the need to relocate utility poles.〔Meier, Terry. "Lighter Loads: Geofoam Shortens Construction Schedules by Reducing the Weight of Embankment Fill and Settlement Time." HubDot. HubDot, 1 Apr. 2010. Web. 18 Nov. 2010. From 2009 to 2012, a Vaudreuil based expanded polymer manufacturing company provided over 625,000 cubic meters (over 22 million cubic feet) of geofoam for a new segment of highway 30 in the province of Quebec (Canada), in the Montreal area, making it the largest geofoam project in North America to date. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Geofoam」の詳細全文を読む スポンサード リンク
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