Performance and Durability of Expanded Polystyrene
Expanded Polystyrene blocks have been used in construction and building projects for over forty years, uses ranging from civil engineering applications such as bridges, roads, and carparks to their use as insulation in residential and commercial buildings as well as cold storage.
One such project that has been monitored and reported on over many years is the Norwegian Public Roads Authorities. In 1972, they adopted the use of EPS as a super light filling 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.
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 several countries in Europe, Asia and North America. At present more than 350 road projects involving EPS fills have been completed in Norway with a volume of totalling some 500,000 m3 of EPS blocks.
The extensive use and testing of Expanded Polystyrene (EPS) as a lightweight filling material for civil engineering projects such and road embankments and bridges in Norway and many other regions has seen both a wider use on a global scale and the introduction of a number of different design applications.
These tests show that in addition to reduced vertical loads, advantages from using EPS may also include reduced horizontal loads, simplified designs, foundations placed directly on EPS blocks and increased speed and ease of performing construction activities.
As the innate cellular structure of expanded polystyrene makes it dimensionally stable, EPS will not deteriorate with age when protected in situ from direct contact or exposure with solvents, temperature extremes, incorrect mechanical load and UV light. The study undertaken in Norway monitoring the effects of time on the performance of EPS have concluded that no deficiency effects are to be expected from EPS fills placed in the ground for a normal life cycle of 100 years.
