Terrafoam EPE
Non-Collapsing, Fully Elastic Fill Suitable for Hydrocarbon Exposures

Product Description

TERRAFOAM EPE is inert closed cell polyethylene foam, with excellent resistance to freeze/thaw, zero capillarity and low moisture absorption. It is manufactured in three densities. TERRAFOAM EPE has the unique capacity to recover virtually 100% after compression/decompression cycling, particularly useful under foundation structures to prevent water accumulation and the subsequent expansive forces from freezing. It is suitable for many hydrocarbon exposures. (See brochure). TERRAFOAM EPE will never rot; support mold or mildew. It is NOT biodegradable.

Applications

• Under structural concrete slabs, pile caps, grade beams and bridge abutments
• Floatation applications
• Packaging, shock and damage protection, container linings
• Client's proprietary fabrications

Engineered Test Methods for Accurate Product Selection

Test methods traditionally used for testing and evaluating foamed polyethylene were developed to measure impact protection in packaging applications. These test methods produce "drop-test" data which do not provide relevant information for evaluating products used in geotechnical applications. Beaver Plastics has developed test methods that measure response to slow-moving, long-term, progressive and cyclic earth forces. These test methods were created to accurately mimic field conditions for time and pressure, producing the most functional and economical choices for EPE density and thickness.

Understanding the Performance of Polyethylene Foam

Polyethylene foam is unique when compared to other void form materials, as most of the resistance to compression is due to entrapped air within its cellular structure. The required thickness calculation involves two separate phases of performance, each with different stress/strain behaviors over time.

Concrete Placement Compression

Immediately on placing fresh concrete, EPE compression is directly related to load. A small amount of air begins to escape and the foam slowly deforms. This first phase of performance is complete with concrete final set and hardening (usually within 8 hours), as it is then self-supporting on the piles. See EPE Charts and Data which show the amount of compression that will take place under fresh concrete at various loads.

Subgrade Expansion Compression

The second phase of performance is the long term compression that occurs when a freezing damp subgrade or clay soil expands upward, creating stress to the EPE and the structure above it. The remaining thickness of EPE (after loss due to Concrete Placement) will be compressed, but is limited to the amount of total uplift restraint of the structure.

Terrafoam EPE Protecting High Pressure Vessel's Foundation from Frost or Clay Swell

“Automatically” Calculating the Required Thickness of TERRAFOAM EPE

Beaver has developed three Terrafoam EPE thickness calculators to help make the correct product and thickness selection for under foundations. They are designed for structures on concrete piles, steel H piles or driven pipe piles. Contact Beaver Technical Services for any assistance required. These spreadsheets use the same format as the manual process below, but do the calculations automatically, especially useful for determining accurate total restraint to uplift of a structure.

Manually Calculating the Required Thickness of TERRAFOAM EPE

Calculate Restraint to Uplift provided by the structure’s total of mass, pile friction resistance, less ad-freezing uplift, divided by the area directly supported by the EPE. (kPa)		kPa
b. Use the Maximum EPE Compression Chart to find the amount of EPE compression from Restraint to Uplift. (%) (Start with EPE15 which may be the most economical solution)		%
c. Establish the Initial Compression Loss from the appropriate Chart. Calculate the concrete load using 24 kPa per metre thickness. (Further compression ends at 8 hrs; 16 hours for a wider margin of safety.) (%)		%
d. Deduct the Initial Compression Loss from Restraint to Uplift (b. minus c.). This difference is the balance of EPE thickness available to absorb soil swell. (%)		%
e. Divide Anticipated Maximum Soil Expansion (mm) by the balance of EPE thickness (%) (from d.) to determine the full EPE thickness required. (mm)		mm

Beaver’s Research Capability

There may be unique applications for EPE that would be subject to different geotechnical conditions than typically expected. Beaver Plastics is able to test virtually any polymeric foam material that could possibly meet the anticipated operating conditions. New data can be produced in a short time in Beaver’s own labs. Please consult with Beaver’s Technology Department for more information.