1. INTRODUCTION
The Geotechnical Engineering Bureau (GEB) provides earthwork and foundation engineering
services for the design and construction of Departmental projects statewide. When subsurface
explorations reveal that a project’s underlying soils are soft or unstable, the GEB may utilize
specialized treatment options to allow completion of the desired final product.
Expanded Polystyrene Fill (EPS) is one such option. It is a lightweight fill used to reduce
vertical stresses beneath embankments, or to reduce lateral stresses on retaining walls, abutments
or foundations. EPS has been used in highway construction in Europe since the early 1970’s and
was first used in New York in 1996. Advantages to using EPS include:
● EPS has a density that is less than 1% of typical soil fills. By using this extremely
lightweight material in an embankment section over a deep, soft organic or clay soil
deposit, significant time and cost savings may be achieved as compared to other
foundation stabilization and settlement mitigation techniques.
● When properly designed as backfill, EPS blocks exert little to no lateral load on retaining
structures.
● A typical block measuring 2 ft x 4 ft x 8 ft (0.6m x 1.2m x 2.4m) at a density of 1.25 pcf
(0.2 kN/m3
) weighs 80 lbs (36 kg). On site, EPS blocks may be easily unloaded by two
laborers and placed into position.
● The composition of an EPS block allows field cutting and trimming by a hand-held “hot
wire” apparatus, hand or power saws to produce desired shapes.
This manual provides personnel in design and construction general information on EPS material
and proper installation techniques.