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Expanded Polystyrene EPS Geofoam is a geotechnical material, being used in construction activities in US, Japan and European Countries since 1960s. Its application in the construction and infrastructure industry is picking up in India.

EPS geofoam is approximately 1% the weight of soil and less than 10% the weight of other lightweight fill alternatives. As a lightweight fill, EPS geofoam reduces the loads imposed on adjacent and underlying soils and structures. EPS geofoam is not a general soil fill replacement material but is intended to solve engineering challenges. The use of

EPS typically translates into benefits to construction schedules and lowers the overall cost of construction because it is easy to handle during construction, often without the need for special equipment, and is unaffected by occurring weather conditions. In addition, EPS geofoam can be easily cut and shaped on a project site, which further reduces jobsite challenges. EPS geofoam is available in numerous material types that can be chosen by the designer for a specific application. Its service life is comparable to other construction materials and it will retain its physical properties under engineered conditions of use.

Soft Soil Remediation

Poor load-bearing soils can be a problem in wide geographic regions or even limited locales with certain adverse conditions. Such soils must be remediated because they do not provide a stable, firm foundation for civil engineering projects or large buildings. Common remediation methods such as surcharging, pile-driving, or over-excavation and replacement with imported soils, are time-consuming and costly.

EPS geofoam provides a simple and cost-effective alternative, as the material is about 100 times lighter than soil, yet can support high applied loads. Additionally, unlike other lightweight fills such as shredded tires or wood chips, EPS geofoam is homogenous and transfers loads uniformly, eliminating differential settlement.

Slope Stabilization

Improving slope stability, whether in new construction or in repair, is an increasingly popular use for EPS geofoam. EPS Geofoam’s low weight makes it an excellent option for stabilizing steep slopes, without the need to change the final slope geometry. As the material is much lighter than other fills, it greatly reduces the weight of a slope’s driving block and lowers the risk of costly and dangerous slope failures. That means it can significantly reduce the pressure and load against the side of a hill and reduce the shear stress on underlying soils, substructures or adjacent structures, decreasing rotational and lateral slope movement. All of this means a more stable slope.

Soil is subject to erosion, which can cause slope failure, but erosion’s not an issue for EPS geofoam. It’s strong (up to 60 psi) with a high compressive resistance rate, so it can stand up to harsh conditions. It won’t rot, deteriorate under normal conditions or decompose over time, making it practically maintenance-free. In addition, EPS geofoam’s closed-cell structure (98% air) inhibits moisture intrusion. EPS geofoam resists vibrations, absorbing the impact of earthquakes and tremors on the slope, to keep it more stable.

Additionally, since slope stabilization generally happens on steep and uneven terrain, using EPS Geofoam simplifies construction since crews can move and place it without heavy earth moving and compaction equipment, drastically speeding up the construction schedule.

Reducing Lateral Pressure on Retaining Structures

Using geofoam for retaining structures provides a reduction in lateral pressure as well as preventing settlement and improving waterproofing. Geofoam's light weight will reduce the lateral force on a retaining wall or abutment.

Retaining walls are subjected to dead loads from backfill and adjacent structures, live loads and other loads from the vicinity of the structure. Retaining walls may be vulnerable due to sudden increase in lateral loads from adjacent structures, live loads from traffic loading, etc. By introducing a suitable compressible material between retaining wall and backfill, lateral pressures acting on the retaining wall can be substantially reduced. EPS geofoam is one of the compressible inclusions which readily compresses under application of load due to its lower density and higher stiffness compared to other materials.

Embankment Fill to Reduce Settlement

Lightweight embankment fill can both improve embankment stability by reducing driving forces and reduce consolidation (settlement) of compressible foundation soils. Geofoam is approximately 1% of the weight of traditional fill and therefore, very effective in reducing driving forces and settlement loads. Typical geofoam embankment fills consist of a sand leveling course, geofoam blocks, membrane cover for separation and solvency (gasoline) protection, pavement system for proper load transfer to the geofoam, and side slope cover embankment.

Embankments using geofoam allow for a great reduction in necessary side slopes compared to typical fills. Reducing the side slope of the embankment can increase the usable space on either side. These embankments can also be built upon soils affected by differential settlement without being affected. Maintenance costs associated with geofoam embankments are significantly lower when compared to embankments using natural soil.

Stress Reduction on Buried Utilities

Many utilities including underground pipes, tunnels and ducts require a structural fill to protect them from external compression and for insulation purposes. A lightweight fill material like geofoam blocks is an appealing choice for construction projects that have buried utilities for multiple reasons. Not only is it sturdy and can take high compression rates, it is light enough so that it does not add any additional load on buried utilities that are often not designed to have weight placed on them. Additionally, the lightweight EPS material allows it to be an extremely efficient form of insulation. It helps to protect against fluctuating temperatures so that the utilities can function properly without interruption.

Aside from its lightweight property that makes it the preferred material to protect buried utilities, foam blocks are easy to shape and handle. This factor is highly relevant when installing geofoam around buried utilities that often have all types of shapes, sizes and angles.

Compressible Inclusion against Expansive Soil

Another application for utilizing EPS geofoam is to use it as a compressible inclusion adjacent to a structural element when it is in contact with expansive soil. Expansive soils or swelling soils are those soils that have the tendency to increase in volume when water is available and to decrease in volume if water is removed.

Swelling pressure of expansive soils can impose significant threat to the infrastructure built on them. Placing of compressible inclusion material, such as expanded polystyrene (EPS) geofoam, in expansive soils can effectively reduce the swelling pressure acting on the structure.