Geotextile characteristics

October 1, 2023  |  Q&A: GMA Techline

Q: I have two nonwoven heat-bonded geotextile filters: one made of polyester and the other made of polypropylene. They look the same but are giving very different hydraulic performance. Can you explain this phenomenon?
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LLDPE yield point

October 1, 2023  |  Q&A: GMA Techline

Q: Can you tell me why my linear low-density polyethylene (LLDPE) is currently showing a yield point? In years past, we have not seen this happen.  
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Four Pillars Of Geosynthetic Sustainability

August 1, 2023  |  Q&A: GMA Techline

Q: How is geosynthetic sustainability as compared with conventional construction materials like soil, concrete and steel?
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Bridging or trampolining during liner installation

August 1, 2023  |  Q&A: GMA Techline

Q: Why is it required that there be no bridging or trampolining during liner installation at any temperature?
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Equipment on deployed geosynthetics

August 1, 2023  |  Q&A: GMA Techline

Q: I’m hoping you can resolve a disagreement among coworkers regarding construction quality assurance (CQA). I’m asking what is published and/or your opinion. It involves traffic on geomembrane. Is it now industry standard to allow skid steers and/or ATVs to operate directly on a geomembrane? It…
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Seeding procedures for erosion control blankets and turf reinforcement mats

August 1, 2023  |  Q&A: GMA Techline

Q: Do I seed below or above erosion control blankets (ECBs) or turf reinforcement mats (TRMs)?
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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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