Expanded polystyrene (EPS) blocks, commonly referred to as geofoam blocks, are lightweight, closed-cell geosynthetic materials used in geotechnical engineering applications. Their mechanical and physical properties are defined by relevant standards according to product class, and they are characterized by a high strength-to-density ratio.
Geofoam blocks are manufactured from expandable polystyrene beads through pre-expansion, conditioning and molding processes. In Türkiye, geofoam blocks are generally produced as prismatic blocks with widths of 100–120 cm, lengths of 200–500 cm and heights of 50–60 cm. Due to their lightweight nature, they can be easily transported and placed on site without the need for heavy construction equipment.
Because of their closed-cell structure, geofoam blocks have low water absorption. They are lightweight fill materials whose mechanical properties improve with increasing density, manufactured using a controlled and proven production technology. Geofoam is non-biodegradable, recyclable and easy to install on site. Owing to these physical and mechanical advantages, geofoam has been used since 1972 as an alternative geotechnology to conventional methods in a wide range of geotechnical engineering applications.
Geofoam applications are becoming increasingly widespread both in Türkiye and worldwide due to their short construction time, ease of installation, reduced labor requirements, and ability to provide faster and more economical solutions compared with conventional methods.
Geofoam is a material whose compressive strength increases with density, and its compressive strength-to-density ratio is high compared with other lightweight fill materials. Geofoam block design is carried out by considering project-specific deformation criteria and design loads. One of the key advantages of geofoam is that the test conditions for monotonic loading and its behavior under loading are defined by international standards.
Geofoam Material Designations and Minimum Physical and Mechanical Performance Requirements According to ASTM D6817
| Material Designation (ASTM D6817) | Density (kg/m3) | Compressive Strength at 1% Strain (kPa) | Compressive Strength at 5% Strain (kPa) | Compressive Strength at 10% Strain (kPa) |
| EPS12 | 11.2 | 15 | 35 | 40 |
| EPS15 | 14.4 | 25 | 55 | 70 |
| EPS19 | 18.4 | 40 | 90 | 110 |
| EPS22 | 21.6 | 50 | 115 | 135 |
| EPS29 | 28.8 | 75 | 170 | 200 |
| EPS39 | 38.4 | 103 | 241 | 276 |
| EPS46 | 45.7 | 128 | 300 | 345 |
EPS Block Material Designations According to TS EN 14933
| Material Designation (TS EN 14933) | Test Specimen |
| Compressive Strength at 10% Deformation (kPa) | |
| CS(10)40 | ≥ 40 |
| CS(10)50 | ≥ 50 |
| CS(10)60 0 | ≥ 60 |
| CS(10)70 | ≥ 70 |
| CS(10)80 | ≥ 80 |
| CS(10)90 | ≥ 90 |
| CS(10)100 | ≥ 100 |
| CS(10)120 | ≥ 120 |
| CS(10)150 | ≥ 150 |
| CS(10)200 | ≥ 200 |
| CS(10)250 | ≥ 250 |
| CS(10)300 | ≥ 300 |
| CS(10)350 | ≥ 350 |
| CS(10)400 | ≥ 400 |
| CS(10)450 | ≥ 450 |
| CS(10)500 | ≥ 500 |
REFERENCES
- ASTM D6817. Standard Specification for Rigid Cellular Polystyrene Geofoam
- TS EN 14933. Thermal insulation and lightweight fill products for civil engineering applications – Factory-made products of expanded polystyrene (EPS) – Specification.
- EN 14933. Thermal insulation and lightweight fill products for civil engineering applications – Factory-made products of expanded polystyrene (EPS) – Specification
- ASTM D4439. Standard Terminology for Geosynthetics