Expanded Polystyrene (EPS) blocks may be used as a light fill material in road embankments or behind retaining structures in order to solve both stability and settlement problems due to soft subsoil conditions.   

Expanded Polystyrene blocks have been used in construction and building projects for over forty years, with uses ranging from civil engineering applications such as bridges, roads, and carparks, through to wall insulation in residential and commercial buildings, including cold storage. 

One such project well monitored and reported has been the adopted use of EPS as a super light filling material in road embankments across Norway since 1972. The study of the effects of time on the performance of the EPS concluded that no deficiency effects are to be expected from EPS fills placed in the ground for a normal life cycle of 100 years. [Read more on the long term performance and durability of EPS for civil engineering projects]

To complete the recent road upgrade for the Port of Melbourne Port Capacity Project, Foamex M Grade Expanded Polystyrene (EPS) blocks were chosen. Foamex EPS blocks were selected for this project because of their inherent lightweight nature as well as the quality of the M Grade blocks. [Read more on this specific project requirements and EPS usage.]

VicRoads has also chosen to use EPS in embankments to minimise embankment loading and to reduce settlement to an acceptable level. These embankments vary in height up to about 4m, however, it is possible to build EPS embankment fills to greater heights. 

According to a VicRoads Technical Paper review of the use of expanded polystyrene for the construction of embankments over weak ground, EPS offers the following advantages:

Can provide a cost effective method of embankment construction where ground improvement and/or ground support would be required for conventional fill.

Significant reduction in construction time, where staged construction and/or surcharging may be required for conventional fill.

Significant reduction in the risk of failure of the embankment during construction on very weak or highly compressible ground.

Significant reduction in maintenance costs, where differential settlement and/or long-term secondary compression are anticipated for conventional fill.

Can reduce differential settlement between approach embankments and rigid structures.

Can reduce down-drag effects when widening embankments on weak ground.

May avoid the need for relocation of services sensitive to settlements and/or lateral ground movement induced by embankment construction.

Rapid embankment construction can be achieved, even at sites with difficult access, as the EPS blocks can be lifted and moved easily by hand.

Once the embankment base has been prepared, the embankment may be completed in poor weather conditions.

Foamex expanded polystyrene blocks have a range of advantages that make them ideal for civil engineering projects. Their durability, strength and flexibility, coupled with their dimensionally stable quality and low water absorption makes them an ideal, long term lightweight fill.

Image with Thanks to EPSIndustry.org