Expanded Polystyrene Geofoam (Geofoam) is a lightweight, rigid foam plastic engineered to a unit density of 1 to 2 pounds per cubic foot thus producing a material that is approximately 100 times lighter than most soils. Manufactured as a lightweight molded block, Geofoam can be easily cut to any size or shape at the job site. Geofoam may be used for:
- Embankment construction over soft ground
- Protection of underground structures
- Reduction of lateral load on walls and abutments
- Slope stability remediation
Geofoam delivers these advantages:
- Low induced stress and settlement
- Proven durability
- Material does not decay or chemically react when placed in the ground
- Easily transported, handled, and placed
- Can construct in poor weather
- Speed - Speed - Speed
- Can be covered to appear as a normal slope embankment or wall
- There are no known environmental concerns (30 years experience)
On Tuesday, June 22, 2004, at Quonset Point, R.I., the Rhode Island Department of Transportation (RIDOT), the Federal Highway Administration (FHWA) Resource Center and the University of Rhode Island Transportation and LTAP Centers co-hosted a Showcase on Geofoam demonstrating one of FHWA's "Market Ready Technologies". To assure that this Showcase would effectively demonstrate Geofoam's installation advantages in less than ideal weather conditions, the Showcase Development Committee deliberately chose June 22, historically a rainy day in Rhode Island.
During the morning session engineers from the FHWA Resource Center and Parsons Brinkerhoff Quade & Douglas, Inc covered the history and provided a technical overview of EPS Geofoam technology. RIDOT representatives provided background on the Showcase's Davisville Railroad Bridge Project No. 369 and representatives from the contractor and manufacturer also shared real-time Geofoam experiences.
Participants from seven states including local agencies braved the weather for the visit to the actual working site. This site was selected since it illustrated how the use of Geofoam allowed for reuse of an existing bridge abutment and back wall, thus saving money and time. The site, which was 30ft tall, 40ft wide and 100ft long, was immediately adjacent to an active rail line, another reason for saving the existing abutment. Five workers could safely and efficiently construct the approach embankment even though it was next to the rail line.
Some US highway projects that have benefited from EPS Geofoam include:
- I-93 Central Artery Project (Big Dig), Massachusetts
- I-15 Mainline and Ramp Fill, Utah
- Eden Prairie Swamp Project, Minnesota
- Embankment over Peat Bog, Indiana
- H-3 Project, Truck Escape Ramp, constructed during rainy season, Hawaii
- Embankment Failure Repair, Colorado
- Route 23 Slope Failure Repair, New York
