Construction of Highway Embankments Using Geofoam Blocks

Highway embankments to be constructed over soft clay deposits require specialized geotechnical solutions. Where conventional compacted soil embankments are preferred under such ground conditions, an appropriate ground improvement method is selected and implemented to address bearing capacity and settlement problems. Construction of the compacted soil embankment is then carried out following completion of the ground improvement works. Conventional ground improvement technologies such as stone columns, bored piles, jet grout columns, impact-driven crushed-stone columns, prefabricated vertical drains (PVDs), surcharge loading, vacuum consolidation, deep mixing and similar methods are widely used both internationally and in Türkiye. However, completion of ground improvement works can extend the time required to open the project to traffic and, depending on the depth of the ground requiring improvement, can also increase construction costs.

As an alternative to ground improvement followed by conventional compacted soil embankment construction, roadway embankments over weak ground can be constructed without ground improvement by using geofoam blocks, which can be up to 100 times lighter than conventional soil fill. This method was first implemented in 1972 by the Norwegian Public Roads Administration (NPRA) (Aabøe et al., 2019). The NPRA designed a geofoam block solution for the approach embankment of the Flom Bridge on Highway No. 159 near Oslo, and implementation of this solution prevented the development of excessive total settlements in the completed roadway. This first application in the world remains in service under operational loads today (Aabøe et al., 2019). As the technology became more widespread, the Norwegian Road Research Laboratory (NRRL) published a specification for the use of geofoam blocks in highway construction (NRRL, 1992).

Flom Bridge geofoam approach embankment in Norway

World’s first geofoam block highway embankment: construction of the Flom Bridge approach embankment in Norway, 1972 (Aabøe and Frydenlund, 2011)

Following the successful applications of geofoam technology in Norway, representatives of the Japanese EPS industry established the Expanded Polystyrene Construction Method Development Organization (EDO). Under the leadership of EDO, geofoam technology was first implemented in Japan in 1985 (Tsukamoto, 2011). In the United States, geofoam blocks were first used in 1989 on Colorado State Highway 160. They were subsequently used in the widening and reconstruction of Interstate 15 in Utah between 1998 and 2001 (Bartlett et al., 2000). As the use of geofoam became more widespread and accepted in the United States, a design guideline for highway embankments constructed using geofoam blocks was developed through research funded by the National Cooperative Highway Research Program (NCHRP) (Stark et al., 2004a; 2004b).

I-15 Reconstruction Project in Utah

I-15 Reconstruction Project, Salt Lake City, Utah, 1998–2001 (Source: S. F. Bartlett website)

In addition to Norway, applications involving the use of geofoam blocks in highway projects as an alternative to conventional ground improvement methods have been reported in the Netherlands (Duškov and Nijhuis, 2011), Germany (Beinbrech and Hillmann, 1997), France (Perrier, 1997), the United Kingdom (Thompsett et al., 1995), the Czech Republic (Herle, 2011), Greece (Papacharalampous and Sotiropoulos, 2011), Finland (Saarelainen and Kangas, 2001) and Serbia (Spasojević et al., 2011). As applications became more widespread across Europe, the European Manufacturers of Expanded Polystyrene (EUMEPS) developed both material standards addressing the mechanical and physical properties of geofoam blocks and design guidance for their use (EUMEPS, 2014). In addition to the United States and European countries, the technology is also known to have been used in Russia, China, South Korea and Taiwan (Aabøe et al., 2019). In addition to providing very short construction durations, highway embankments constructed using geofoam blocks may also have lower initial construction costs than ground improvement followed by conventional compacted soil fill, depending on the depth of the ground requiring improvement (Duškov and Waarts, 2011; Özer et al., 2012). Because geofoam provides an effective solution for controlling both total and differential settlements, it can also help minimize maintenance costs throughout the service life of highways.

Geofoam block highway embankments can be constructed either with a trapezoidal cross-section or with vertical sides inclined at 90 degrees to the horizontal. Where required, both construction configurations may also be combined along the same alignment. Typical field construction stages include:

  • Placement of the sand leveling layer
  • Placement of geofoam blocks
  • Construction of the reinforced concrete load distribution platform
  • Covering the geofoam embankment slopes with a geomembrane followed by soil cover
  • Construction of the roadway subbase and base courses followed by hot-mix asphalt pavement
Trapezoidal geofoam block highway embankment

Trapezoidal geofoam block highway embankment

Vertical-sided geofoam block highway embankment

Vertical-sided geofoam block highway embankment with a 90-degree inclination to the horizontal

Since 2017, numerous geofoam block fill projects have been implemented in Türkiye with Geotech Soil and Foundation Engineering providing project design services, including preparation of design reports and construction-level block layout plans, field implementation supervision, and instrumentation and monitoring services. These projects can be accessed through the links below:

O-4/O-1 Eurasia Tunnel Link Road Geofoam Embankment

REFERENCES

  • Aabøe, R., Frydenlund, T. E. (2011). 40 years of experience with the use of EPS geofoam blocks in road construction. Paper presented at the 4th International Conference on Geofoam Blocks in Construction Applications, Lillestrøm, Norway, June 6–8, 2011.
  • Aabøe, R., Bartlett, S. F., Duškov, M., Frydenlund, T. E., Mandal, J. N., Negussey, D., Özer, A. T., Tsukamoto, H., Vaslestad, J. (2019). Geofoam Blocks in Civil Engineering Applications. In: Arellano D., Özer A., Bartlett S., Vaslestad J. (eds) Proceedings of 5th International Conference on Geofoam Blocks in Construction Applications (EPS2018), Kyrenia, May 9–11, 2018, 3–38.
  • Bartlett, S. F., Negussey, D., Kimblei, M., Sheeley, M. (2000). Use of geofoam as super-lightweight fill for I-15 reconstruction. Transportation Research Board 79th Annual Meeting, Washington, DC.
  • Beinbrech, G., Hillmann, R. (1997). EPS in road construction—Current situation in Germany. Geotextiles and Geomembranes, 15 (1–3), 39–57.
  • Duškov, M., Nijhuis, E. (2011). Lightweight road embankments for the crossover of the N207 over the railway Alphen A/D Rijn-Gouda. Paper presented at the 4th International Conference on Geofoam Blocks in Construction Applications, Lillestrøm, Norway, June 6–8, 2011.
  • Duškov, M., Waarts, P. (2011). Cost comparison of construction methods for highway widening on compressible subgrade. Proceedings of the 4th International Conference on Geofoam Blocks in Construction Applications, EPS 2011, Lillestrøm, Norway.
  • European Manufacturers of Expanded Polystyrene (EUMEPS) (2014). EPS White Book. EUMEPS background information on standardisation of EPS, version 15/10/2014.
  • Herle, V. (2011). Design and monitoring of EPS embankment on D1 near Ivanovice in the Czech Republic. Paper presented at the 4th International Conference on Geofoam Blocks in Construction Applications, Lillestrøm, Norway, June 6–8, 2011.
  • Norwegian Road Research Laboratory (NRRL) (1992). Use of expanded polystyrene in road embankments—design, construction and quality assurance. Public Roads Administration, Oslo, Norway.
  • Özer, A. T., Kiziroğlu, S., Akyol, Y., Ateş, E. (2012). Economic Analysis of Ground Improvement Methods for Bridge Approach Embankments Constructed over Soft Clay Deposits. Fifth National Geosynthetics Conference, G5 2012, Boğaziçi University, Istanbul, May 24–25, 2012, 165–176.
  • Papacharalampous, G., Sotiropoulos, E. (2011). First time application of expanded polystyrene in highway projects in Greece. Paper presented at the 4th International Conference on Geofoam Blocks in Construction Applications, Lillestrøm, Norway, June 6–8, 2011.
  • Perrier, H. (1997). Ultra light cellular structure – French approach. Geotextiles and Geomembranes, 15 (1–3): 59–76.
  • Tsukamoto (2011). History of R&D and design code for EDO-EPS method in Japan. Paper presented at the 4th International Conference on Geofoam Blocks in Construction Applications, Lillestrøm, Norway, June 6–8, 2011.
  • Saarelainen, S., Kangas, H. (2001). Behavior of an old EPS light-weight fill at Vammala, Finland. Proceedings of the 3rd International Conference on Geofoam Blocks in Construction Applications, EPS 2001, Salt Lake City, Utah, USA.
  • Spasojević, S., Mitrović, P., Vujanić, V. et al. (2011). The application of EPS in geotechnical practice: a case study from Serbia. Paper presented at the 4th International Conference on Geofoam Blocks in Construction Applications, Lillestrøm, Norway, June 6–8, 2011.
  • Stark, T. D., Arellano, D., Horvath, J. S., Leshchinsky, D. (2004a). Geofoam applications in the design and construction of highway embankments. NCHRP Web Document 65 (Project 24-11).
  • Stark, T. D., Arellano, D., Horvath, J. S., Leshchinsky, D. (2004b). Guideline and recommended standard for geofoam applications in highway embankments. NCHRP Report 529, Transportation Research Board, Washington, D.C., http://trb.org/publications/nchrp/nchrp_ rpt_529.pdf.
  • Thompsett, D. J., Walker, A., Radley, R. J., Grieveson, B. M. (1995). Design and construction of expanded polystyrene embankments: Practical design and methods as used in the United Kingdom. Construction and Building Materials, 9(6): 403–411.