The challenge of geomembrane wild edge thickness

August 1, 2023  |  Q&A: GMA Techline

Q: Over the past several years, we have seen a reduction in thickness of the weld edge (smooth edge) of textured geomembranes. This is presenting a challenge for installers when trying to achieve passing trial seams in the field prior to production welding. Destructive seam tests are passing, but ju…
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Hybrid TMAX Calculating

June 1, 2023  |  Q&A: GMA Techline

Q: As of 2020, there are new, updated designs for mechanically stabilized earth walls in AASHTO. In short, there are new methods to calculate the maximum force (Tmax) that incorporates design methods for extensible reinforcements (i.e., geosynthetics). They include limit equilibrium and stiffness me…
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Geomembrane Residual Stress

June 1, 2023  |  Q&A: GMA Techline

Q: We are getting a lot of uncertainty with our ASTM D5397 single-point notched constant tension load (SP-NCTL) stress crack testing. Can you shed some light on the situation? This uncertainty is frustrating our field personnel and holding up a rather large HDPE geomembrane liner installation for a …
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The ASTM D1505 Method

June 1, 2023  |  Q&A: GMA Techline

Q: I want to measure the density of a mineral-filled composite polymer mixture by the ASTM D1505 method. What liquid will be used for density measurement (density >1)? The products to be tested are made of either polypropylene or polyethylene with calcium carbonate and additives. We will be addin…
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Geomembrane welding below freezing

June 1, 2023  |  Q&A: GMA Techline

Q: Can geomembrane welding be done below freezing (32 degrees Fahrenheit [0 degree Celsius])? If it can be done, is there a method or preferred procedure to assure its success?
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Understanding Geomembrane Asperity

April 1, 2023  |  Q&A: GMA Techline

Q: Twice in the past few weeks colleagues asked me the same question about geomembrane asperity, so I come to you to understand it. 
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Strip or Sheet Drain Vs. French Drain

April 1, 2023  |  Q&A: GMA Techline

Q: What are benefits to using “strip or sheet drain” over conventional French drain construction with soils?
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Geosynthetics for Precipitate Clogging

April 1, 2023  |  Q&A: GMA Techline

Q: We are retrofitting a highway edge drain where rubberized concrete was used as the base course layer. What type of geotextile or geosynthetic should we consider for this project’s drain?
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Dewatering Bags for Erosion and Sediment Control

April 1, 2023  |  Q&A: GMA Techline

Q: How does a dewatering bag (Dirt Bag, sediment container, Siltsack, etc.) work on a construction site to help you with your erosion and sediment control plan?
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Landfill Gas Emissions Modeling

February 1, 2023  |  Q&A: GMA Techline

Q: I’m writing to see if you are aware of any research on landfill gas (LFG) emissions modeling through various geomembranes, particularly for temporary covers? 
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