As a geotechnology, “Geofoam Blocks” were first used in 1972 by the Norwegian Public Roads Administration (NPRA). The NPRA designed a geofoam block solution for the approach embankment of the Flom Bridge on Highway No. 159 (Oslo Ring Road), and its implementation prevented the development of excessive total settlements in the constructed roadway. This first geofoam application in the world remains in service under operational loads today.
Türkiye’s first geofoam block roadway embankment was constructed in 2017 in the Üsküdar district of Istanbul, northwest of the intersection of the Istanbul Ring Road (O-1 Motorway) and the D100 Highway. The project was designed to divert part of the heavy traffic from the Uzunçayır exit of the O-1 Motorway toward Acıbadem instead of Harem.
The fact that the world’s first geofoam block roadway embankment remains in service after more than 50 years, together with data collected over a seven-year period from instrumentation stations in Türkiye, demonstrates that geofoam blocks can maintain their performance under service loads without undergoing significant mechanical or physical degradation.
Questions regarding whether geofoam blocks will degrade, decay, lose their physical and mechanical properties, or even disappear completely during their service life are among the most frequently asked questions about geofoam technology.
During the final stages of construction of the Fikirtepe Interchange, Türkiye’s first geofoam block roadway embankment was closed to traffic after more than 6.5 years of service. Following the closure, the roadway embankment was removed to allow construction of viaduct foundations within the scope of the Fikirtepe Interchange project. During this process, the geofoam blocks were carefully removed and stockpiled.
Two blocks were randomly selected from the stockpile to examine the dimensional and physical properties of geofoam blocks that had been subjected to service loads for more than 6.5 years. An initial visual inspection showed that the block dimensions were nearly identical to those of virgin factory-produced blocks (width: 1.20 m, length: 2.50 m, height: 1.00 m) and that the block surfaces remained smooth, similar to those of unused blocks.
Following the visual inspection, the blocks were transported to the laboratory. The geofoam block was sliced into 5 cm thick sheets using an automated hot-wire cutting machine. Following a sampling protocol designed to represent the entire block, 5 × 5 × 5 cm cubic specimens were prepared, and compression tests were performed in accordance with ASTM D1621.
The compression test results showed that the geofoam blocks, after carrying dead and live design loads for more than 6.5 years, exhibited compressive strengths that were nearly identical to those of virgin geofoam blocks.
In summary, this project, which holds the distinction of being Türkiye’s first geofoam block roadway embankment, continued to contribute to the development of geofoam block geotechnology even after being taken out of service. Physical inspections and mechanical testing conducted on the geofoam blocks, which had supported dead and live design loads for more than 6.5 years, demonstrated that the blocks had not lost their physical or mechanical properties under the design loads.
Finally, it should be emphasized that geofoam block geotechnology represents an engineered solution, and its ability to maintain its physical properties over the long term depends on appropriate engineering design, material selection and implementation.
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REFERENCES
- Özer, A. T., Akınay, E. (2024). Construction of Geofoam Block Embankments atop Existing Infrastructure in Transportation Projects. Geosynthetics International, Volume: 31, No. 1, 94–112.
- Özer, A. T., Akınay, E. (2022). Frequently Asked Questions in the Construction of Geofoam Block Highway Embankments. 18th National Conference on Soil Mechanics and Geotechnical Engineering (ZMGM18), Erciyes University, Kayseri, September 29–30, 385–394.
- Özer, A. T. (2020). Geofoam: EPS Block Applications in Civil Engineering. Austrotherm Türkiye, Istanbul, Türkiye. ISBN: 978-605-69266-0-0.
- Özer, A. T., Akınay, E. (2019). First Geofoam Roadway Embankment Application of Turkey. 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, 71–80.
- 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.
- Özer, A. T., Akınay, E. (2017). Evaluation of the Short-Term Performance of a Geofoam Block Roadway Embankment Based on Instrumentation Monitoring. 7th Geotechnical Symposium with International Participation, Istanbul Technical University, Istanbul, November 22–24, 891–902.