Plasti-Fab® GeoSpec® Lightweight Fill Material for Road Embankments

Plasti-FabI am sure you have been driving along, and seen sights like the one below, where the edge of the road is crumbling or breaking away because of the soil beneath.

road_embankOften poor soil conditions exist at rivers, muskegs or bogs where a bridge structure is supported on a firm foundation either directly or by piles. The road embankment is at increased depth due to the ground profile and the problem of soil settlement is emphasized.

Solutions to these settlement problems could include re-aligning the road to place it over firm ground. Alternatively, geotechnical engineers have long recognized the utility of using lightweight fill to reduce mass and associated gravitational driving forces.

Plasti-Fab GeoSpec Lightweight Fill Material is one of these solutions. GeoSpec lightweight fill material is typically at least 50 times lighter than other types of lightweight fill materials. GeoSpec lightweight fill can be used as a prefabricated fill in an area where it would be difficult to establish a compacted fill due to space limitations, adverse weather conditions, or site access.

Road projects across Canada have used Plasti-Fab GeoSpec lightweight fill to solve their soil conditions. One such example is the Highway 69 project that occurred in Ontario. The Ontario Ministry of Transportation began a massive construction project to widen Highway 69, a major north-south thoroughfare in northeastern Ontario. Between Estaire and Sudbury, the highway intersects the Canadian National Railway, causing engineers to construct a 300-meter long bridge over the railroad tracks. In order to achieve maximum durability and stability of the bridge structure, highway design engineers AECOM specified expanded polystyrene (EPS) fill material at the bridge abutments.

ontario bridge“The benefits associated with the use of EPS in embankment construction include the improvement of foundation stability, reduction of long-term settlement and reduction of the overall construction schedule,” said Jason Lee, a geotechnical engineer at Thurber Engineering, who worked as a geotechnical consultant for AECOM on the project.

Plasti-Fab GeoSpec lightweight fill material can be designed to withstand high compressive loads, but has a density less than one percent of traditional earth fill materials. The design properties of GeoSpec fill material are stable and very little lateral load is induced on adjacent structures when vertical load occurs. Earth fill material, in comparison, shifts and settles over time, meaning additional stress can be induced on bridge abutments and other concrete structures.

“Due to schedule constraints, the bridge structure was completed first and the approach fills constructed later,” said Lee. “The use of EPS in this project aimed at reducing the differential settlements (between the approach fill and bridge abutments) and limiting the lateral pile movements in the foundation of the bridge.”

O.C.P. Construction Supplies, a distributor for Plasti-Fab, provided more than 10,000 cubic meters of GeoSpec fill material for the bridge abutments. The material was installed by Teranorth Construction, a subcontractor of Pioneer Construction, who served as general contractor on the project.

“GeoSpec provides a unique solution for a lot of geotechnical engineering applications,” said Roland Bélanger, Senior Representative and GeoFoam Specialist for Plasti-Fab in Ontario and Quebec. “It was able to speed up the construction time of the Highway 69 bridge, provide a stable base for long-term durability, and reduce the stress against the structure itself.”

If you want to learn more about GeoSpec Lightweight Fill Material, visit our web site: or see some videos of the GeoSpec projects on YouTube.

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