Repeatability and reproducibility in geosynthetics

October 1, 2021  |  Q&A: GMA Techline

Q: If repeatability and reproducibility are high, it is a positive output, but high repeatability and reproducibility will give high uncertainty from Equation 1: uncertainty = sqrt (repeatability^2 + reproducibility^2. Could you explain to me why it looks like it is contradictory?
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Measuring strain in geosynthetics

October 1, 2021  |  Q&A: GMA Techline

Q: Currently, what is the best-known method to measure strains in geosynthetics? We are having arguments between results generated from crosshead movement and extensometers.
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Residual strength of a geosynthetic clay liner

October 1, 2021  |  Q&A: GMA Techline

Q: I was wondering if I could get some input about the residual strength of a geosynthetic clay liner (GCL). We have lab results where it is “flatlining” for the residual case (Figures 1 and 2, and Tables 2–4). The GCL is proposed for use in a landfill cell with ultimately a maximum of 98 feet…
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Design of a CCR composite liner system

August 1, 2021  |  Q&A: GMA Techline

Q: We are designing a composite liner system for a coal ash landfill. From the bottom-up, the cross section is subgrade soil, geosynthetic clay liner (GCL), geomembrane, composite drainage layer with nonwoven geotextiles on both sides and then ash from coal combustion residuals (CCR). Do you have an…
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A geotextile filter for an edge drain

August 1, 2021  |  Q&A: GMA Techline

Q: I am doing a geotextile filter design for a highway edge drain. All I have from the site is a grain size analysis of the sandy subgrade soil. Can you point me in the right direction?
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Bluff repair in seismically active zone

August 1, 2021  |  Q&A: GMA Techline

Q: I am doing a bluff repair on the West Coast in a seismically active zone. Can you direct me to where I can get some design guidance?
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Service life of nonwovens

August 1, 2021  |  Q&A: GMA Techline

Q: Where can I find literature on the useful service life of nonwoven geosynthetic fabrics installed in soils?
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Metal leaching from geosynthetics

August 1, 2021  |  Q&A: GMA Techline

Q: Geosynthetics are made from polymers that use metal-based catalysts in their formulations. Do geosynthetics have the potential to leach metals into the environment?
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Bringing geomembranes into equilibrium with atmosphere

August 1, 2021  |  Q&A: GMA Techline

Q: Some ASTM test methods request that one brings the specimens into equilibrium with the atmosphere prior to the test (some of them determine the conditions: 21±2ºC and 60±10% relative humidity). Considering that we just produce polyethylene geomembranes, and they are not significantly affected …
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OIT for UV and oven aging

June 1, 2021  |  Q&A: GMA Techline

Q: I am contacting you in regard to the requirements for oxidative induction time (OIT) (standard [STD] and high pressure [HP]) in the GRI-GM13 specification for both ultraviolet light and oven aging. Do you need to conduct both OIT tests or just one or the other?
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