TerraFlex™ Elasticized Geofoam is also beneficial when rehabilitating
or retrofitting existing structures by adding an increased safety factor
against one or more geotechnical and/or structural failure mechanisms
such as seismic forces and expansive soils and rock. When a compressible
inclusion is required with a drainage component refer to the Geoinclusion® manufactured by GeoTech Systems Corporation.
Other materials such as bales of hay or straw, wood chips, and cardboard
have been used in compressible inclusion applications worldwide since
the early 20th Century. However, these materials are unpredictable in
their mechanical and physical behavior.
Using TerraFlex™ Elasticized Geofoam will provide predictable and consistent
mechanical (stress-strain-time) behavior that is totally under the control
of the design engineer.
TerraFlex™ is a revolutionary geosynthetic product
with the following attributes:
Composition and Materials: TerraFlex™ Elasticized
Geofoam is a cellular plastic material that is strong, but has very low
density (1% of traditional earth materials). The parent material, TerraLite
Geofoam, is a manufactured block material meeting the engineered product
specification standards of ASTM C 578 and CGSB 51.20. The nominal (average)
density of the parent material is 12 kg/m3 (.75 lb/ft3).
- Increased compressibility compared to normal EPS (TerraLite Geofoam),
- Predictable mechanical behavior,
- Provides thermal insulation
- Provides noise and vibration damping,
- Will not decompose,
- Will not contaminate the environment,
- Resistant to insect infestation.
TerraFlex™ Elasticized Geofoam contains Perform Guard®.* Perform Guard
is made under a patented process** which uses a natural mineral that is
formulated to resist insects and builds it right into the product.
TerraFlex™ is unaffected by normally occurring weather at time of installation
and will retain its physical properties under pre-engineered conditions
of use. TerraFlex™ is made under a Quality Assured manufacturing process
monitored by a third party laboratory.
Size and Shape: TerraFlex™ is produced in block form and is easily fabricated
to required dimensions for individual projects. The molded blocks have
dimensions of 901.7 mm (35.5") x 1257.3 mm (49.5") x 4927.6
mm (194.0"). The blocks are then subjected to an additional manufacturing
process of elasticization that increases the flexibility characteristics
of the material.
Environmentally Safe: TerraFlex™ contains no CFC's, HCFC's, HFC's, or
formaldehyde. It is inert, non-nutritive and highly stable. It will not
decompose, decay, or produce undesirable gases or leachates. TerraFlex™
is recyclable and safe for WTE Systems and landfills.
Limitations and Cautions: TerraFlex™ stands up well to normal weather
conditions encountered during installation. Long-term (6 months or greater)
exposure to UV radiation will cause discoloration. Material should be
covered as soon as practical.
TerraFlex™ is unaffected by freeze thaw cycling, moisture,
or road salts. Protect TerraFlex™ from exposure to hydrocarbons, highly
solvent extended mastics and coal tar pitch.
TerraFlex™ contains a flame retardant additive; however, it
should be considered combustible and should not be exposed to open flame
or any source of ignition.
Applicable Standards: TerraFlex™ is a proprietary product with physical
properties that have been altered during the manufacturing process of
elasticization. The parent material, TerraLite, is manufactured with third-party
(UL) certification to be in compliance with ASTM C 578 Type XI specifications.
The block molding process of the parent material also includes additional
voluntary, proprietary quality control standards and additives of GeoTech
*Tested against termites and carpenter ants. Manufacturer has specific
species on file. Perform Guard is a registered trademark of the AFM Corporation.
**Protected under U.S. Patents No. 5,194,323 and No. 5,720,108. Other
U.S. and Foreign Patents Pending. 1997 AFM Corporation.
Technical Data: To select the required thickness
of TerraFlex, the design professional should develop project-specific
design curves relating deformation of the ground surface and stress at
the ground surface from the expanding ground. In general, the largest
stress occurs under confined (zero deformation) conditions and the largest
deformation occurs under free-swell (zero stress) conditions. The designer
must select a magnitude of surface stress and corresponding deformation
that is intermediate to these limiting conditions and for which the structure
will be designed.
Note: In the absence of data relating surface stress and deformation,
the designer can use deformations estimated using free-swell tests and
arbitrarily select a stress level for which the structure will be designed.
Graph 1 shows the stress-strain relationship of
TerraFlex™ Elasticized Geofoam in rapid loading, unconfined axial compression
at a strain rate of 10% per minute at room temperature. To determine the
thickness of TerraFlex™ required for project specific conditions Graph
1 is used to estimate the strain level in the Geofoam.
- Find the stress magnitude for which the structure will be designed
on the vertical axis.
- Move horizontally to the appropriate stress-strain curve. For the
most conservative design, the rapid loading curve should be used. For
greater economy under conditions when the ground expansion is expected
to develop over an extended period of time, one of the extended time
curves in Graph 2 can be used. For geofoam strains greater than approximately
40%, only the rapid loading curve should be used.
- Move vertically downward and scale off the corresponding Geofoam strain
The required thickness of Geofoam is the calculated using the following
Geofoam Thickness =
(Design magnitude of surface
deformation x 100)
TerraFlex™ strain (in %)
Using this simple approach, different combinations of stress transmitted
to the structure and Geofoam thickness can be evaluated to find the most
cost effective design.
Graph 2 shows isochronous
stress - strain curves for different durations of loading for TerraFlex™
The stress-strain curves were developed using the results of unconfined
axial compression creep tests.
TerraFlex™ Elasticized Geofoam can be used in the following applications.
Other engineered applications may also be appropriate.
- Earth retaining structures.
- Buried Pipes
- Bridge abutments,
- Bermed structures, and
- Slabs on grade.
For most applications the following guidelines apply. Additional
guidelines for specific applications should be developed by the design
- At time of material delivery, verify Quality Assurance and identification
marks on face of the product.
- Surfaces should be clean, dry and sound; free of excessive dust, dirt,
loose paint, oil, grease or any foreign matter that would interfere
with a good bond.
- Apply an approved adhesive as required by Architect/Engineer to TerraFlex.
Place walnut sized daubs of adhesive alternately spaced every 8"
- 12" apart across the surface of the TerraFlex™ board, beginning
3" from the edges.
- Set TerraFlex™ board in place immediately. Press firmly over the entire
surface to level board and establish good adhesive contact. Butt all
board joints tightly.