Scratch impact on HDPE liners

April 1, 2022  |  Q&A: GMA Techline

Q: I have a project where multiple and extensive scratches were created on the high-density polyethylene (HDPE) liner for a reservoir due to poor construction practices. (See the following Figures 2–4.)
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Sand fines overlying geocomposite

April 1, 2022  |  Q&A: GMA Techline

Q: We are working at a site with a permitted landfill cell with a leachate collection system that includes a drainage geocomposite with 12 inches (305 mm) of leachate collection sand overlying it. My question has to do with the percentage of fines in sand on a geocomposite. Our leachate collection p…
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Geotextile filtration clogging resistance

February 1, 2022  |  Q&A: GMA Techline

Q: I have a question about the Filter Criteria in the Federal Highway Administration (FHWA) Filter Design procedure, specifically the clogging resistance equation 2-10. This seems to require a particularly large pore size; for example, if the D15 of the soil was for 70 microns, the minimum O95 of th…
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Sewn versus welded seams

February 1, 2022  |  Q&A: GMA Techline

Q: On your website list of sample questions and answers (https://geosynthetics.ifai.com/programs/gma-techline), a question is asked about a recommendation for sewn versus welded seams for geotextiles. Bob Koerner answered this question by stating that you have done a study for joining geosynthetic c…
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EPDM geomembrane for a water application

February 1, 2022  |  Q&A: GMA Techline

Q: We are looking at a life-cycle study for the usefulness of an ethylene propylene diene monomer (EPDM) based geosynthetic liner for a water conservation application. Request to kindly share the information for our study. Regards.
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Geosynthetics for pipe wrapping

February 1, 2022  |  Q&A: GMA Techline

Q: I need an impervious geosynthetic to wrap a pipe that will be placed within a heavy clay. Do you have any suggestions?
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Fusion-welded HDPE geomembrane patch

February 1, 2022  |  Q&A: GMA Techline

Q: I need to make sure of what the minimum area is for an HDPE geomembrane with a 60-mil (1.5-mm) thickness patch that should be fusion welded instead of extrusion welded. Also, when does one need to replace a panel that is damaged (i.e., the percent of damage allowed to be repaired)?
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Electrical leak detection at depth

February 1, 2022  |  Q&A: GMA Techline

Q: I am taking the opportunity to ask a question about the electrical leak detection (ELD) test for geomembranes: We have the area covered with silt from the past rainy season, and it is estimated to be about 5 feet (1.5 m) deep worst-case scenario. The liners in this area were not properly inspect…
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ABS geosynthetics product types

February 1, 2022  |  Q&A: GMA Techline

Q: Infrequently, I note geosynthetic products manufactured using acrylonitrile butadiene styrene (ABS) (e.g., geogrid, binding line, a few molded specialty products). Can you provide a summary of most of the geosynthetic product types using ABS, as well as the general benefits and limitations of ABS…
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Heat resistance of geomembranes

October 1, 2021  |  Q&A: GMA Techline

Q: We have a question in regard to the heat resistance of geomembranes. We are interested in paving a road over a geomembrane with hot mix asphalt and want to know if the geomembrane will continue to function as a moisture barrier?
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