Development and Information Dissemination Regarding EPS as a Lightweight Construction Material by Tor Erik Frydenlund, Geir Refsdal and Roald Aabøe.
When a major research project on frost action in soils was carried out by the Norwegian Public Roads Administration (NPRA) during the period 1965 to 1973 this included the investigation of various insulation materials for frost protection of roads like 50 to 100 mm thick boards of foamed glass, extruded polystyrene (XPS) and expanded polystyrene (EPS). In this connection also fatigue tests were performed. It was then concluded that EPS material could sustain the repetitive stresses occurring in a road structure and the idea of applying EPS in greater layer thickness than boards emerged in 1972 when the NPRA initiated the use of EPS as a super light fill material in road embankments. The first project involved the successful reconstruction of road fills adjacent to a bridge founded on piles to firm ground. Prior to reconstruction, the fills, resting on a 3 m thick layer of peat above 10 m of soft marine clay, experienced a settlement rate of more than 200 mm per year. By replacing 1 m of ordinary fill material with two layers of EPS blocks, each layer with 0,5 m thickness, the settlements were successfully halted. When placed the EPS blocks had a density nearly 100 times lighter than the replaced materials. In order to protect the method from patent claims the concept of lightweight road embankments and other possible similar applications were published in a major weekly technical journal in Norway at the time of the first construction.
Since then authorities in several countries have also found the method advantageous for building roads across soft ground and for other construction purposes where low loads are essential. In addition to reduced vertical loads, advantages from using EPS may also include reduced horizontal loads, simplified designs, foundations on EPS and increased speed and ease of performing construction activities. The method is now in common use in many countries in Europe, Asia and America.
NPRA has in this connection been approached by and assisted public authorities and private companies in many countries regarding technology transfer related to the EPS-method. In 1979 inquiries were made by the Laboratoire Central des Ponts et Chausses (LCPC) in France and in 1983 their first test fill was constructed in Montpellier. Assistance has also been given to road authorities and interested parties in Finland, Estonia, Denmark, Germany, the Netherlands, Ireland, the UK, the former Republic of Yugoslavia, Italy, Greece, Portugal, Spain, USA, Canada, Mexico, Japan, South Korea, the Philippines, Malaysia and Thailand. Several other countries have also implemented the method with specifications based on experience from countries mentioned above (e.g. Sweden, China assisted by Japan etc.).
At the first international conference on EPS held in Oslo in 1985, a total of 150 delegates participated with several countries represented. Following the conference, an agreement on technology transfer was signed with the EPS Development Organisation (EDO) in Japan and this has resulted in a mutual fruitful cooperation over many years. Similar agreements have been established with the French organisation SCREG, a Malaysian company and an institution in South Korea.
Through participation in the PIARC (World Road Association) committee on Earthworks, Drainage and Subgrade assistance was given in connection with preparation of the PIARC Publication (in French and English) on "Lightweight Filling Materials” released in 1997 with a chapter on the EPS method. Information has also been presented at conferences and seminars in Vancouver, Canada; Honolulu, USA; Seoul, South Korea; Kuala Lumpur, Malaysia; Galway, Ireland; Delft, the Netherlands; Rostock, Germany and France as well as at the International conferences on EPS in Tokyo, Japan 1996, Salt Lake City, Utah, USA in 2001 and Lillestrøm, Norway in 2011.