Geosynthetics October/November 2022 - 8

Q &
GEOGRID DURABILITY
AND CEMENT
THE GEOSYNTHETIC
INSTITUTE ANSWERS
YOUR QUESTIONS
gmatechline@textiles.org
View past questions and answers
at geosyntheticsmagazine.com/
category/gma-techline.
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for fast, free, direct technical answers.
Q: I am searching for data or specifications
pertaining to long-term degradation
resistance of geogrid exposures to cement-
more specifically, cement-treated soils. Your
assistance would be greatly appreciated.
A: Thank you for your question on geogrid
durability in the presence of cement.
This is not an issue for most polyolfin
(polypropylene [PP] and polyethylene
[PE]) geogrids. Such polymers are very
resistant to the pozzolanic reaction byproducts
and the heat of hydration caused
by curing cement in concrete. However,
this is not the case for geogrids made of
polyethylene terephthalate (polyester PET)
yarns. A good reference for this is Hsuan
and Koerner (2005). It might also interest
you that with the rising quantity of plastic
waste generation around the world, there
has been growing attention regarding the
consumption of waste materials in the
production of construction materials such
as concrete and asphalt. Due to the need
and scale of this issue, there is a promising
future in the utilization of recycled
plastics from both a sustainability and
a durability perspective.
Hsuan, Y. G., and Koerner, R. M. (2005). " Evaluation of
the hydrolysis behavior of polyethylene terephthalate
yarns. " Proc., GRI-18 Conf. on Geosynthetics R&D in
Progress, GeoFrontiers, Austin, Texas, Paper no. 1.11.
A
GMA TECHLINE
MODERATED BY
George R. Koerner
UNDERWATER WICK
DRAIN INSTALLATION
Q: We have an underwater wick drain
application in the Delaware River adjacent
to the Delaware Memorial Bridge. S. T.
Hudson Engineers Inc. is working with the
Delaware River & Bay Authority (DRBA) on
a ship collision protection system (SCPS)
at the piers in the river. There is up to 50
feet (15 m) of organic clay at the locations
of eight new 80-foot (24-m) diameter flat
sheet pile cellular structures. Do you have
any guidance regarding installation of
wick drains in 45 feet (14 m) of water? The
concept is to install the wick drains prior to
installing the cells and then filling the cell
with 65 feet (20 m) of granular fill.
A: The Sunzo Foundation Engineering Co.
has a beautifully made YouTube video on
this subject showing the entire underwater
prefabricated vertical drain (PVD/wick drain)
installation in a stepwise process.
Process: " Marine PVD Installation Barge PVD
Construction Dedicated Ship, https://www.
youtube.com/watch?v=Z8yVoW73C70&ab_
channel=amysunzo
I have seen this done for the Hong Kong
airport and several other large projects.
Please realize that the contractor needs
to construct a 100-foot (30-m) dome to
accommodate the depth of the 50-foot (15m)
soil layer plus the 45-foot (14-m) depth of
water. The stability of which, particularly in
high winds, needs to be considered.
8
Geosynthetics | October November 2022
http://www.geosyntheticsmagazine.com/ https://www http://www.youtube.com/watch?v=Z8yVoW73C70&ab_
Geosynthetics October/November 2022

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