Background and most recent GRI standards
Geosynthetics | August 2007
By Bob Koerner
In the 1980s, while supervising graduate research students in their geosynthetics theses topics, the issue of writing generic and standardized procedures arose in this (quite new at the time) geosynthetics field. Rob Swan generated our first formalized test methods with what became GRI-GG1: “Geogrid Rib Tensile Strength” (now ASTM D6637) and GRI-GG2: “Individual Geogrid Junction Strength.”
Through the subsequent years many more standards were promulgated by students and mainly by Drs. George Koerner and Grace Hsuan. A good percentage of these standards (29%) were subsequently adopted in whole or part by ASTM.
We made the decision to group our GRI standards by geosynthetic type rather than application area and continue to do so. Please note that we continue to use the GRI (Geosynthetic Research Institute) designation since all of our standards have in-house research and development testing involved in their development. The following table lists our current standards, which include specifications, guides, practices, and test methods.
The specifications, guides, and practices are registered under U.S. copyright and are also available free via the GSI Home Page, www.geosynthetic-institute.org. It is the latest version that is always online. The test methods are available at a nominal price. The entire collection of 54 GRI Standards are available for $100 plus shipping and handling. Commentary on some of the newer standards follows:
- Geotextile tubes for erosion control, dewatering, and now decontamination of polluted river and harbor sediments are a growing application area. We have available the modification of Jack Fowler’s original concept of a “hanging bag” test for assessing if a given fabric type is suitable for a given dredged soil type. It is available as the GRI-GT14 test method.
- Biaxial geogrids are used for roadway and airfield stabilization and one potential test method to assess their performance is the “torsional rigidity” test when subjected to in-plane rotation. It is a modification of Dr. Tom Kinney’s original test and is available as the GRI-GG9 test method.
- “Temporary landfill covers” are used to prevent or retard landfill gasses from release into the atmosphere. Cost-wise, however, a thick permanent geomembrane is not warranted for a relatively short 5-10 year lifetime. Thus a specification for lightly reinforced polyethylene geomembranes is available. It is GRI-GM22 and addresses properties for three different thicknesses.
- GCL testing is known to be difficult insofar as gripping the upper and lower geotextile surfaces in a large direct shear box. Borrowing from Dr. Pat Fox’s research, we have used his “end platens” in our GRI-GCL4 test method. It is currently available with photos and graphic details.
- Another new GCL standard is a practice for taking “undisturbed field samples” for subsequent hydraulic conductivity testing. Developed by Dr. George Koerner, it is designated as GRI-GCL5.
- In the geocomposite area, we have two recent test methods both directed toward “geosynthetic (geofoam) gravel.” They were developed by George Koerner. One test method is focused on mechanical deformation behavior, the other on hydraulic behavior. They are designated GRI-GC9 and GRI-GC10, respectively. They are currently undre consideration by ASTM for possible adoption.
Needless to say, as time progresses please look for new standards to be developed by GRI in all geosynthetic areas. It is exciting for us to be key players in the important process of advancing the industry through standardization.
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Comments are the opinion of individual posters and do not reflect the views of Geosynthetics or Industrial Fabrics Association International.
9:48 am CDT
RE: Prices and installation
To: Nando and Anom
You are best served by contacting GM and GCL manufacturers and distributors directly. There are many excellent choices in this regard in the annual Specifiers Guide.
P.S., The 2011 Specifier’s Guide is available in December 2010.
6:44 pm CDT
liner price list
can I get the latest price for installation of single HDPE liner and GM/GCL? including material price. is it big difference (cost) between the two type?
the geomembrane used in GM/GCL, it has the same thickness with the one in single hdpe membrane or not?
6:18 pm CDT
RE: RE: liner comparison
Thanks for the explanation. Really appreciate your help.
Regarding cost factor, can you give me detail price of material and installation for single geomembrane and GM/GCLs? I really need that for my assignment. Thanks a lot.
Best regard,
Nando
1:13 pm CDT
RE: liner comparison
Web team note: We received the following response to your comment from Dr. Robert Koerner of GSI:
Nando,
Regarding cost, the HDPE geomembrane (GM) by itself is the lowest cost, the GM/CCL (compacted clay liner) is the highest cost, and the GM/GCL (geosynthetic clay liner) is intermediate between the two.
Regarding installation, the three options are in the same order.
Regarding performance, there are fundamental differences. Here the GM/GCL is the best in its performance as measured by leakage rates, the GM by itself is the poorest, and the GM/CCL is intermediate.
With regard to the performance comparison, data from 279 landfill cells is available for corroboration. Clearly, composite GM/GCL liners are preferred for containment systems of all types.
Bob Koerner
Geosynthetic Institute and the GMA Techline
www.geosynthetic-institute.org
gmatechline@ifai.com
6:16 pm CDT
liner comparison
dear sir/madam
which one is the most effective liner (inc. cost, installation, and performance), using single geomembrane (HDPE) liner, compacted clay liner with hdpe layer above, or using geomembrane (HDPE) GCLs?
please, I need an explanation. thanks.
regard,
nando
1:04 pm CST
Please see listings related to geomembranes in the annual Specifier’s Guide produced by Geosynthetics magazine.
10:50 am CDT
geomembrane machine selection
dear sir/madam
we are looking for a suitable machine to producing hdpe geomembrane.
if you have any information about manufacturers of geomembranes machine please tell us
sincerely yours,
M.RAHMANI
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