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Universal Specification for Geofoam Fills

This specification has been prepared for modification and use in the specifying of Geofoam for highway embankments and related uses. There are components in this specification that may not be relevant for particular jobs (such as a load distribution slab), which can be deleted as appropriate. The document variables are provided to make it a simple matter to insert the project specific elements of associated documents into this specification. Where these variables are not used in projects, they can be edited out.

The structure of this specification is in eight sections:

1. Description
2. Material (including physical properties)
3. Sampling and Testing
4. Protection (including criteria for acceptable damage)
5. Subgrade Preparation
6. Placement
7. Connectors
8. Geomembrane

Document Variables: Substitute values as needed for specific project specification
[XXX1] = Technical Agreement Memorandum # Releasing specification
[XXX2] = Related Work Section (Concrete)
[XXX3] = Related Work Section (Structural Steel)
[XXX4] = Compaction Requirements Section
[XXX5] = Gradation Requirements Section
[XXX6] = Load Distribution Slab Requirements Section

This document is formatted to be printed using a non-proportional font (Courier) in 12 point size.



This specification has been released per Technical Agreement Memorandum No. [XXX1]


1.1 The work provided herein consists of furnishing all material, and equipment and placing Synthetic Ultra Light Weight Block Fill, referred to in this specification as Geofoam, complete, as specified herein, shown on the plans, or as directed by the Engineer.

1.2 Reference Publications.

Some or all of the publications referred to hereinafter form a part of this specification to the extent referenced. The publications are referred to in the text by the basic designation only. The latest edition of the referenced publication shall govern.

American Society of Testing Materials (ASTM) Publications:

ASTM Test Method for
C203 Breaking Load and Flexural Properties of Block-Type Thermal Insulation
D732 Strength of Plastics bv Punch Tool
C272 Water Absorption of Core Materials for
Structural Sandwich Construction
D1621 Compressive Properties of Rigid Cellular
D1622 Apparent Density of Rigid Cellular Plastics

D1623 Tensile and Tensile Adhesion Properties
of Rigid Cellular Plastics
D3345-74 Insect Resistance (ants, termintes, etc)

1.3 Related Work

Section [XXX2]--Portland Cement Concrete
Section [XXX3]--Structural Steel


The Geofoam shall be produced by a manufacturer with an in place, third party certification, Quality Control program which is monitored by an independent testing organization.

Geofoam shall be fabricated using virgin feedstock manufactured into blocks having no more than fifteen percent regrind content. Blocks shall have a height of at least 890 mm (35 inches), a width of at least 1.22 m (48 inches), and length of at least 2.44 (96 inches). All blocks shall be smooth and flat, and are within tolerances of 0.5% of respective height, width and length dimensions. Additional field and/or shop trimming and cutting will be required as necessitated by the geometry of the fill being constructed.

Geofoam blocks shall have the following physical properties:

Physical Properties of TerraLite EPS Geofoam
Density, min., kg/m 3, ( lb/ft3 ) 11.2
Compressive Resistance
@ 1% deformation, min., kPa (psi)
Flexural Strength min., kPa (psi) 69
Water Absorption by total
immersion, max., volume %
4.0 4.0 3.0 3.0 2.0
Oxygen Index, min.,
volume %
24.0 24.0 24.0 24.0 24.0
Buoyancy Force (kg/m3)


The Geofoam shall contain a flame retardant additive and shall have UL Certification of Classification as to External Fire Exposure and Surface Burning Characteristics. Geofoam should be considered combustible and should not be exposed to open flame or any source of ignition.

All Geofoam blocks shall be treated by the manufacturer with a tested and proven termite treatment for below grade applications, 3 year minimum field exposure. The termite treatment agent shall be an EPA registered material.

The Contractor shall furnish the Engineer with two copies of the third party certified test report showing that the Geofoam blocks meet the physical proprties and standards listed above.

GeoTech TerraLite™ manufactured by licensees of GeoTech Systems Corporation, 9912 Georgetown Pike, Suite D-2, Great Falls, Virginia 22066, (703) 759-0300, is an approved material.


Quality assurance testing and sampling, to monitor the conformance of the Geofoam fill with the specification requirements, will be completed as directed by the Engineer. Density and geometry (dimensional tolerances) testing shall be conducted using full-sized blocks. Blocks in conformance with contract requirements can be used to make required fills.

Testing to monitor the quality of the Geofoam shall be done at the discretion of the Engineer. Engineer has the right to random sample the manufacturing plant. If any block does not conform to the physical requirements or if it is damaged in any way, it may be rejected by the Engineer.


The Contractor shall prevent damage to the Geofoam during delivery, storage, and construction. Prior to delivery of Geofoam fill to the project site, the Contractor shall review and be thoroughly knowledgeable with the manufacturer's care and handling recommendations. Any Geofoam fill to be exposed to sun light for more than six months shall be covered with reflective material which will prevent ultraviolet light degradation.

The Contractor shall protect the Geofoam blocks from: (1) Organic solvents such as acetone, benzene, and paint thinner; (2) Petroleum based solvents such as gasoline and diesel fuel; (3) Open flames.

Placement of embankment will require special procedures and careful selection of appropriate construction equipment to prevent damage to the Geofoam fill. No heavy construction equipment or vehicles shall be allowed directly on the Geofoam.

Damage to Geofoam shall be corrected as follows:

Slight damage ( <0.0034 cubic meter (0.l2 cubic feet) with no linear dimension > 305 mm (l ft)) may be left in place as-is.

Moderate damage (<0.01 cubic meter (0.35 cubic feet) with no linear dimension > l m (3.3 ft)) shall be filled with sand.

Geofoam blocks with excessive damage (i.e. exceeding the "moderate" category) shall be replaced with Geofoam blocks which meet the damage criteria. Geofoam blocks not meeting the damage criteria may be cut to eliminate the excessive damage and the remaining undamaged portion of the block may be used within the fill, provided the undamaged portion of the block meets all other requirements.

Embankment over the side slopes of the Geofoam fills shall be placed starting at the bottom of the slope in such a manner as to prevent damage to the Geofoam. Finished Geofoam on side slopes shall have a minimum of 0.6m embankment cover.

The embankment material, in areas beyond the lateral distances necessary to protect Geofoam from damage, shall be compacted per the [Applicable] Specifications Section [XXX4]. The intent of this requirement is to minimize the uncompacted zone around the Geofoam wall.


5.1 Clear and grub site.

5.2 Dewater site as required.

5.3 Place a leveling course of drain blanket material (See Section [XXX5] of the [Applicable] Specifications for gradation) over the prepared surface, 200 mm (8 inch) thickness minimum. Level to ±10 mm over 3 meters (1/2" per 10') horizontal.


Geofoam fill shall be placed to the lines and grades shown in the plans and as directed by the Engineer. The surface of a layer of Geofoam blocks to receive additional Geofoam blocks shall be constructed with a variation in surface tolerance of no more than 15 mm (0.05 foot) in any 3 m (10-foot) interval. All blocks shall accurately fit relative to adjacent blocks. No gaps greater than 20mm (0.07ft) will be allowed on vertical joints. The finished surface of the Geofoam fill beneath pavement sections shall be constructed to within the tolerance of zero to minus 60 mm (0.2 foot) of the indicated grade. The finished surface of the Geofoam fill on side slopes that receive soil cover shall be constructed to within a tolerance of plus 90 mm (0.3 foot) to minus 90 mm (0.3 foot) of the indicated grade.

Blocks placed in a row in a particular layer shall be offset 0.6 m (2.0') relative to blocks placed in adjacent rows of the same layer as shown on the plans. In order to avoid continuous joints, each subsequent layer of blocks shall be rotated on the horizontal plane 90 degrees from the direction of placement of the previous layer placed.

When needed to prevent blocks sliding during embankment construction, connector plates should be placed between horizontal layers of blocks. For the number required, refer to Section 7 of this specification.

Blocks shall be cut using a saw or hot wire.

Because of the light unit weight of the Geofoam fill, it is the Contractor's responsibility to provide temporary weighting and/or guying as necessary until all the blocks are built into a homogeneous mass, and the pavement section as well as any soil cover are in place.

[If a load distribution slab is utilized...]
During placement of the load distribution slab over the top surface of the Geofoam it is permissible to use rebar supports (dobies) to support the reinforcing steel during concrete placement. The Geofoam would be considered soil as referenced in Section [XXX6] of the [Applicable] Specifications.


Connectors shall be galvanized steel or stainless steel multi-barbed connectors. Each connector shall have a lateral holding strength of at least 60 lbs when tested with Type I Geofoam, with a safety factor of two.

Install a minimum of 3 connectors for each 1.2m x 2.4m section of Geofoam material or as shown on plans or directed by the Engineer. Press firmly into the rigid foam until the connector is flush with the surface. Position the next foam block as specified and seat firmly before placing subsequent blocks.



Geomembrane (gasoline-resistant) shall consist of a separate, puncture-free geomembrane. The geomembrane shall be flexible and, by its own weight, shall cover and conform closely to 90 degree edges and corners of Geofoam blocks at ambient temperatures above 45 degrees Fahrenheit, without additional heating of the geomembrane.


The geomembrane shall be reinforced or unreinforced geomembrane. It shall be manufactured from a tri-polymer consisting of polyvinyl chloride, ethylene interpolymer alloy, and polyurethane or a comparable polymer combination. It shall meet the following physical and chemical requirements, specified as minimum or maximum, not average roll properties:

Thickness, mils Minimum 28
ASTM D 751

Unleaded Gasoline Vapor Maximum 0.40
Transmission Rate, ounces
per square foot per 24 hours
ASTM D 814

Grab tensile strength, pounds Minimum 600
both machine and cross direction
(1-inch grip 4-inch x 8-inch sample)
ASTM D 751

Elongation at break. percent Minimum 2O
ASTM D 751

Toughness, Minimum l4,000
grab tensile times percent
elongation for example:
620 pounds x 23% = 14,260

Puncture resistance, pounds Minimum 800
ASTM D 751 (ball tip)

Cold crack, pass degrees Fahrenheit -30
ASTM D 2136
(1-inch mandrel, 4 hours)

Factory Seams Minimum 2
Bonded width, inches each seam

Shear, pounds Minimum 320
ASTM D 751
(modified per National Sanitation
Foundation Std. No. 54)
Fail in base geomembrane material

A Certificate of Compliance shall be furnished stating that the selected geomembrane has been tested. and it meets the above mentioned requirements, and is:

a. Free from pinholes, tears, and other defects which would cause leakage of liquids through the geomembrane.

b. Acceptable for spill containment of hydrocarbons, including automobile gasolines, aviation gas, diesel fuel, kerosene, hydraulic fluid, methanol, ethanol, mineral spirits. and naphtha.


No construction equipment shall drive directly on the geomembrane. Damage to the geomembrane resulting from the Contractor's vehicles, equipment, or operations shall be replaced or repaired with new materials to the satisfaction of the Engineer.

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GeoTech Systems Corporation.

GeoTech Systems Corporation
PO Box 1045
Great Falls, VA 22066
703 759 0300

Last Modified: January 7, 2005