Geofoam is expanded polystyrene (EPS) or extruded polystyrene (XPS) manufactured into large lightweight blocks. The primary function of geofoam is to provide a lightweight void fill for construction on soft ground (highway, bridge approach, embankment or parking lot, etc.). EPS Geofoam minimizes settlement on underground utilities. Geofoam is also used in much broader applications, including lightweight fill, green roof fill, compressible inclusions, thermal insulation, and (when appropriately formed) drainage. 

Now last time when we looked at the expanded polystyrene (EPS) business more commonly known by its trademarked brand “Styrofoam” in South Africa, the takeaway was that the focus should be on higher-margin applications such as building materials, in that case, insulation. Now we look at it as a geotechnical material used as a soil fill replacement material to solve engineering challenges.  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. Here is a product – geofoam is essentially made from expanded polystyrene, and the main difference between geofoam and the foam chunks you get in packaging is the size. While it has a more specialised application it has a much higher income potential .

Applications for geofoam
Slope stabilization
Reduced digging
Retaining structures
Utility protection
Pavement insulation

Real-world examples include:
Road Construction
Landscaping and Slope Stabilization
Insulation and Foundation
Entertainment and Sporting Facilities,

From a geotechnical perspective, the benefits are clear Geofoam has low density and high strength, it is is 1% to 2% the density of soil with equal strength. There are other advantages (and some disadvantages as well).

Market Potential
How big is the market in SA? There is one supplier that I know of, but you have to remember that there is very little infrastructure development and maintenance happening in SA (not even our roads are being maintained). So it might be a good niche export candidate for the rest of Africa.

I have seen some case studies of it being used in the mining industry, which can be read below:
Case studies using EPS geofoam for mining and energy
Geofoam solution for underground coal mine tunnel

Image credit: W.carter