1. Introduction to Cellular Geosynthetics (Geofoams and Geocombs)
A Manhattan College Center for Geotechnology
Technology Transfer through Distance Learning Program Educational Product
Presentation prepared by
John S. Horvath, Ph.D., P.E.
Professor of Civil Engineering
Director/Center for Geotechnology
Manhattan College
School of Engineering
Bronx, New York, U.S.A.
© 3 September 2001 by John S. Horvath. All rights reserved.

2. Manhattan College · School of Engineering · Center for Geotechnology
Construction Material Changes
improvements to traditional materials (steel and PCC)
development of new functions (roles) and applications
for existing materials
development of new materials
use of recycled waste materials 02
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3. Manhattan College · School of Engineering · Center for Geotechnology
Construction Material Changes
improvements to traditional materials (steel and PCC)
development of new functions (roles) and applications
for existing materials <<< geocombs and some geofoams
development of new materials <<< some geofoams
use of recycled waste materials <<< some geofoams 03
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4. Manhattan College · School of Engineering · Center for Geotechnology
Geofoam ...
Generic term for any closed-cell foam used in a geotechnical application that is manufactured either in a fixed plant or in-situ from an expansion process using a blowing agent:
polymeric (plastic)
polyethylene (PE)
expanded polystyrene (EPS) <<< predominant
extruded polystyrene (XPS)
polyurethane (PUR)
glass (cellular glass)
cementitious 04
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5. EPS block in temporary storage after molding.
The entire block weighs less than the person handling it! 05
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6. Example of one of at least three different designs of
EPS-shape geofoam "anti-buoyancy" blocks
developed in Japan (dimensions in millimetres). 06
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7. Manhattan College · School of Engineering · Center for Geotechnology
Geocomb ...
… the newest "geo" material (geosynthetic), formerly referred to as "structures alveolaires ultra légères" (SAUL) or "ultra light cellular structures" (ULCS) in France where it was developed and has been used since the 1980s.
… defined as an open-cell (honeycomb shaped in cross-section) polymeric (PP, PVC) material created by an extrusion process. Typically supplied as a panel- or block-shaped final product. 07
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8. Manhattan College · School of Engineering · Center for Geotechnology
typical tube (~ 25 mm/1 in)
PP (left) and PVC (right) geocombs. 08
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9. Manhattan College · School of Engineering · Center for Geotechnology
Benefits of Using Geofoams and Geocombs
efficient use of solid material
work with the forces of nature, not against them
can be useful for both new construction and with existing structures, permanent and temporary, all climates/weather, "good" and "poor" ground
provide unique geosynthetic functions
can be multifunctional in many applications
compatible and synergistic with other types of geosynthetics 09
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10. Manhattan College · School of Engineering · Center for Geotechnology
Overview of Design Process
design by function to identify desired properties
define parameters for desired analyses and obtain relevant technical information for these parameters
generally treat as an equivalent earth material and use conventional geotechnical analytical methods
economic assessment (construction + O&M)
relevant standards and specifications 10
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11. Manhattan College · School of Engineering · Center for Geotechnology
Geosynthetic Functions
thermal insulation (1960s) >>> geofoams only
lightweight fill (1970s) >>> geofoams & geocombs
drainage (1970s) >>> geofoams & geocombs
noise/vibration damping (1980s) >>> geofoams only
compressible inclusion (1980s) >>> geofoams only
structural (1990s) >>> geofoams only 11
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12. Manhattan College · School of Engineering · Center for Geotechnology
Important Aspects of Material Behavior and
Other Technical Issues for Design
index properties
mechanical (stress-strain-time) behavior
thermal properties
constructability and safety
durability
environmental impact 12
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13. Manhattan College · School of Engineering · Center for Geotechnology
Factors to Consider in an Economic Assessment
design aspects of initial construction
constructability aspects of initial construction
reduced costs of operation and maintenance 13
Manhattan College · School of Engineering · Center for Geotechnology

14. Standards and Specifications
standards constitute technology documentation and are the foundation of any technology
specifications are the project-specific application of relevant standards to define the minimum acceptable results in a given application 14
Manhattan College · School of Engineering · Center for Geotechnology
Manhattan College · School of Engineering · Center for Geotechnology

15. Thermal Insulation Benefits life-cycle energy cost savings
construction cost savings
improved geotechnical/structural performance 15
Manhattan College · School of Engineering · Center for Geotechnology
Manhattan College · School of Engineering · Center for Geotechnology

16. Thermal Insulation Applications
buildings and storage tanks (all climates)
landfill liners (all climates)
shallow buried structures (all climates)
earth retaining structures (cold climates)
pavements and railways (cold climates)
underground conduits (cold climates)
shallow foundations (cold climates) 16
Manhattan College · School of Engineering · Center for Geotechnology
Manhattan College · School of Engineering · Center for Geotechnology

17. Manhattan College · School of Engineering · Center for Geotechnology
Test of landfill-liner thermal insulation alternatives in the U.S.A. 17
Manhattan College · School of Engineering · Center for Geotechnology

18. Manhattan College · School of Engineering · Center for Geotechnology
geofoam
drainage layer
Use of geofoam behind an earth retaining structure to prevent seasonal freezing of the wall drainage system and retained soil.
Note that the drainage system could be incorporated into the geofoam product for overall increased efficiency and reduced cost. 18
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19. Manhattan College · School of Engineering · Center for Geotechnology
Rebuilding an existing road in Norway with geofoam insulation. 19
Manhattan College · School of Engineering · Center for Geotechnology

20. Manhattan College · School of Engineering · Center for Geotechnology
Rebuilding an existing railway in Norway with geofoam insulation. 20
Manhattan College · School of Engineering · Center for Geotechnology

21. Manhattan College · School of Engineering · Center for Geotechnology
geofoam
depth of seasonal
freezing
normal conduit depth
Use of geofoam above an underground conduit to locally modify the depth of seasonal freezing to allow shallower conduit embedment. Note that the geofoam could also be designed to act as a compressible inclusion to reduce forces acting on the conduit. 21
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22. Typical Frost Protected Shallow Foundation concept application. 22
geofoam
depth of
seasonal
freezing
footing depth
without insulation
Typical Frost Protected Shallow Foundation concept application. 22
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23. Lightweight Fill Applications embankments and fills: transportation
water resources
foundation support
architecture and landscaping
earth retaining structure backfill and fills 23
Manhattan College · School of Engineering · Center for Geotechnology
Manhattan College · School of Engineering · Center for Geotechnology

24. Rebuilding a failed road embankment in the U.S.A.
in the winter using EPS-block geofoam. 24
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25. Spraying a PCC facing on a "geofoam wall" type road fill
in the mountains of Japan. 25
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26. Constructing an EPS-block geofoam road embankment in Norway
for a combined bridge approach fill and bridge abutment foundation.
Note the wooden formwork for the abutment footing. 26
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27. Using EPS-block geofoam to construct an abutment backfill
for a new road bridge in Chile. 27
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28. Completed approach embankment and abutment backfill
using EPS-block geofoam for a new road bridge in Canada. 28
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29. Constructing an approach embankment and abutment backfill
using geocomb blocks for a road bridge in France. 29
Manhattan College · School of Engineering · Center for Geotechnology

30. Manhattan College · School of Engineering · Center for Geotechnology
Rehabilitating and raising a levee in the U.S.A. using EPS-block geofoam. 30
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31. Manhattan College · School of Engineering · Center for Geotechnology
Building basement wall in the U.S.A. backfilled using EPS-block geofoam. 31
Manhattan College · School of Engineering · Center for Geotechnology

32. Anchored bulkhead in Japan partially backfilled
using EPS-block geofoam. 32
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33. Barbed connector plates used between blocks of EPS geofoam
in Japan (dimensions are in millimetres, 25 mm = 1 in). 33
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34. 100 mm (4 in) square barbed connector plate
used between blocks of EPS geofoam in the U.S.A. 34
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35. Drainage Applications fluid transmission using geofoams:
ground water around below-grade structures
ground water behind earth retaining structures
leachate collection systems in landfills
ground-borne gases around below-grade structures
fluid transmission and storage using geocombs 35
Manhattan College · School of Engineering · Center for Geotechnology
Manhattan College · School of Engineering · Center for Geotechnology

36. Manhattan College · School of Engineering · Center for Geotechnology
EPS-shape geofoam product developed in the U.K. specifically for collecting and draining ground-borne gases such as methane and radon. Note that it also provides thermal insulation for the structure. 36
Manhattan College · School of Engineering · Center for Geotechnology

37. Geofoam drainage geocomposite available in Asia, Europe and the
glued polystyrene porous block
high-permeability core
Geofoam drainage geocomposite available in Asia, Europe and the
U.S.A. that uses a glued polystyrene porous block core. 37
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38. Geofoam sheet-drain product composed of pieces of
recycled PE that was developed in The Netherlands. 38
Manhattan College · School of Engineering · Center for Geotechnology

39. Drainage (fluid transmission and storage) applications
using geocomb panels and blocks developed in France. 39
Manhattan College · School of Engineering · Center for Geotechnology

40. Noise and Vibration Damping Applications
attenuation of small-amplitude, ground-borne vibrations from:
motor vehicles
trains
attenuation of noise from trains 40
Manhattan College · School of Engineering · Center for Geotechnology
Manhattan College · School of Engineering · Center for Geotechnology

41. Manhattan College · School of Engineering · Center for Geotechnology
EPS-block geofoam
PCC slab
EPS-block geofoam
EPS-block geofoam used to dampen noise and vibrations from a railway in Germany . The EPS blocks directly beneath the tracks are also acting as a lightweight fill for the clay ("Ton") subgrade. 41
Manhattan College · School of Engineering · Center for Geotechnology

42. EPS-block geofoam used to dampen noise and vibrations
PCC ties (sleepers)
PCC layers
EPS-block geofoam used to dampen noise and vibrations
from light-rail vehicles (trams/trolleys) in France and Germany. 42
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43. Compressible Inclusion Applications
lateral earth pressure and settlement reduction:
shear-strength mobilization of "normal" soils
volume change of expansive/freezing soil/rock
structure movement
vertical stress reduction from expansive soil/rock
vertical arching above underground conduits 43
Manhattan College · School of Engineering · Center for Geotechnology
Manhattan College · School of Engineering · Center for Geotechnology

44. tensile reinforcement (optional)
geofoam
soil movement
tensile reinforcement
(optional)
Use of geofoam compressible inclusion behind a rigid/non-yielding earth retaining structure to reduce lateral earth pressures
(optional use of geosynthetic tensile reinforcement also shown). 44
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45. Use of a resilient-EPS geofoam geocomposite in the U.S.A. to act as a
compressible inclusion to accommodate integral-abutment bridge
movement. Drainage is also provided by the same product. 45
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46. Use of a geofoam compressible inclusion around
ground movement
ground movement
ground movement
Use of a geofoam compressible inclusion around
foundation elements of a structure to
reduce stresses in expansive ground (soil or rock) conditions. 46
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47. EPS-block geofoam used as a compressible inclusion around a
reinforced-PCC grade beam in expansive soil in the U.K.
(geofoam also served as formwork during construction). 47
Manhattan College · School of Engineering · Center for Geotechnology

48. Manhattan College · School of Engineering · Center for Geotechnology
EPS-block geofoam used as a compressible inclusion beneath a deep-foundation supported tunnel base slab in expansive ground in the U.K. 48
Manhattan College · School of Engineering · Center for Geotechnology

49. EPS-block geofoam product used as a compressible inclusion beneath
a deep-foundation supported base slab of a building in Canada
(similar product also developed in U.K.). 49
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50. Use of a geofoam compressible inclusion above an
ground movement
ground movement
Use of a geofoam compressible inclusion above an
underground conduit to reduce vertical stresses acting on the
conduit by inducing vertical arching within the overlying soil. 50
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51. Multifunctional use of a geofoam geocomposite only ~ 150 mm (6 in)
thick simultaneously providing compressible inclusion, drainage and
thermal insulation behind a building basement wall in the U.S.A. 51
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52. Structural/Miscellaneous Applications forms for PCC walls
MSEW facing panels
void formers for PCC slabs
crash barriers for motor vehicles and aircraft
impact cushioning for rock sheds
void filling and foundation remediation 52
Manhattan College · School of Engineering · Center for Geotechnology
Manhattan College · School of Engineering · Center for Geotechnology

53. Manhattan College · School of Engineering · Center for Geotechnology
Panels cut from block-molded EPS used as formwork for a reinforced-PCC basement wall in the U.S.A. The EPS also provides post-construction thermal insulation for the life of the structure. 53
Manhattan College · School of Engineering · Center for Geotechnology

54. MSEW system developed in the U.K. with geogrid reinforcement
and facing panels cut from block-molded EPS. 54
Manhattan College · School of Engineering · Center for Geotechnology

55. Generic components of EIFS technology used over EPS and XPS
two-part stucco-like
finish
EPS
mesh reinforcement
underlayment
Generic components of EIFS technology used over EPS and XPS
to create a wide variety of durable architectural finishes. 55
Manhattan College · School of Engineering · Center for Geotechnology

56. Block-molded EPS used as a lightweight void former for a
pile-supported structural slab constructed over a soft subgrade
in the U.S.A. 56
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57. Manhattan College · School of Engineering · Center for Geotechnology
EPS blocks
Credit: Paul Arch Racing Photos
EPS blocks used as crash-cushioning barriers around an auto-racing track in the U.S.A. Note evidence of extensive prior collision damage. 57
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58. EPS blocks used as protection for PCC rock sheds in
mountainous areas in Europe and Japan. 58
Manhattan College · School of Engineering · Center for Geotechnology