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The GMA Techline

August 1, 2019

Moderated by Robert M. Koerner, George R. Koerner and Y. “Grace” Hsuan A geotextile for unpaved driveway/road? Q: Is there any point in using a 150 g/m2 (4.4 oz/yd2) nonwoven geotextile in building an unpaved gravel driveway or gravel road? If so, what should be the most important characteristics of the fabric and what are …

The GMA Techline

June 1, 2019

Who is doing the testing? Q: This question relates to the number of rolls to be selected as the lot sample for specification conformance testing and refers to ASTM D4354. When I look at this standard, it appears the values in Table 1 of GRI’s White Paper #10 refer to the number of units to …

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The GMA Techline

April 1, 2019

Vegetation causing gases under geomembrane? Q: I have a site where we are installing a high-density polyethylene (HDPE) liner in an existing pond. Because of some residual heavy metals in the top layer of soil, I would like to strip off the top 3–6 inches (7.6–15.2 cm) of soil and vegetation. Alternatively, we could mow and …

The GMA Techline

February 1, 2019

Geomembranes for canal lining Q: Our company is an international member of the Industrial Fabrics Association International (IFAI). Our government is planning to line their water canals with a geomembrane to prevent water seepage into the soil. We have been approached by many to suggest the most suitable material with specifications to guide them in …

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The GMA Techline

October 1, 2018

Toxicity of nonwovens? Q: Are there any comprehensive tests (or a general synopsis) of the environmental toxicity of leachate from nonwoven polypropylene fabrics when aged in a freshwater or saltwater solution? Regulatory and municipal bodies in Europe and New Zealand are requesting more info about products that are used in riparian and coastal environments. A: …

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The GMA Techline answers all

August 1, 2018

UV Weathering of Geotextiles Q: My firm is providing construction quality assurance services for a landfill cell expansion. We are having an issue with our contractor and are going to be in a position of having 8 ounces/square yard (271 g/m2) of nonwoven geotextile exposed for a period of time, which exceeds the seven-day limit …

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GMA Techline

February 1, 2018

Determining quantity of recycled HDPE in a geonet Q: I have a question about high-density polyethylene (HDPE) geonets. Is it possible, by thermogravimetric analysis (TGA) and differential scanning calorimeter (DSC) analysis, to determine the quantity of recycled HDPE present in a geonet? I have a geonet that, I think, is made with virgin and recycled …

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GMA Techline

October 1, 2017

Welding HDPE to PVC and more Q: I would appreciate any input you have on these questions: Can a high-density polyethylene (HDPE) geomembrane (GM) be welded to a PVC geomembrane? I am looking to connect a geomembrane to a building foundation. Based on some research, I have found the following options: bolt the geomembrane to …

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GMA Techline

August 1, 2017

Liner repair? Pullout tests? Sewn seams? Shear strength of sludges? Geomembrane liner repair Q: I have a facility that has submitted liner repair documentation for the repair of a high-density polyethylene (HDPE) liner for a leachate/stormwater pond at an industrial landfill site. The repairs were performed using either a patch or, for indentations and small …

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Questions and answers from the GMA Techline

February 1, 2017

Spraying? Shear Strength? Hydraulics? [A more] non-permeable GT? Q: I have received an inquiry for a non-permeable geotextile, which is UV-resistant and will be installed on a long slope for erosion control. Could you kindly recommend a product that would meet these requirements or a solution for this application? Your assistance with this is much …