ASTM formed dimple board standard

June 1, 2022  |  Q&A: GMA Techline

Q: Which American Society for Testing and Materials (ASTM) test would you recommend for tear evaluation of formed dimple board? I am aware of D1004, but can this test be performed on formed dimple board?
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Stacking GCL rolls

June 1, 2022  |  Q&A: GMA Techline

Q: I have a question regarding the storage and handling of geosynthetic clay liner (GCL) rolls. The manufacturer allows stacking up to five GCL rolls. Is this okay?
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Geotextile grab test methods

June 1, 2022  |  Q&A: GMA Techline

Q: I know the American Society for Testing and Materials (ASTM) approves several grips (the requirement is they be “flat”) to perform ASTM D4632 and ASTM D5034. We use a hard, smooth rubber surface for the woven geotextile and a slightly serrated surface for the nonwoven geotextile. One of our c…
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Pipe penetrations through geomembranes

June 1, 2022  |  Q&A: GMA Techline

Q: Is there a recommended detail that you can provide or point me toward for pipe penetrations through geomembrane single and double liners?
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Geotextile impact testing

June 1, 2022  |  Q&A: GMA Techline

Q: We would like to carry out an impact test on geotextiles as described in Koerner (2012), Chapter 2.3.3 Mechanical Properties-Impact Test and Chapter 2.5.5 Impact (Tear) Resistance. I came across the Geosynthetic Research Institute (GRI) GS2 Test Method for Rupture Strength of Geosynthetics by Pen…
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Methane gas geomembrane permeability

April 1, 2022  |  Q&A: GMA Techline

Q: What is the least permeable geomembrane to methane gas? Regarding the permeability of geomembranes to methane gas, could you send me some technical guidelines?
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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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Welding HDPE geomembranes with biogas present

April 1, 2022  |  Q&A: GMA Techline

Q: We are a Brazilian company specializing in biogas plants. We have built a big lagoon biodigester with a high-density polyethylene (HDPE) geomembrane cover. Now the cover is leaking liquid contained in the lagoon: We are organizing the repair procedure, and we would like to first investigate state…
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NSF 61-certified HDPE geomembranes

April 1, 2022  |  Q&A: GMA Techline

Q: Hi, we are looking for options for NSF 61-certified high-density polyethylene (HDPE) liners for installation in a potable water tank, 95th-percentile concentration of free chlorine in the tank is 1.2 ppm (1.2 mg/L). The current liner (60-mil [1.5-mm] textured HDPE, installed in 1999) is damaged a…
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