The GMA Techline

February 1st, 2021

Moderated by George R. Koerner BIOLOGICAL DEGRADATION OF PE AND PP Q: Can you please enlighten me on the biological degradation of polyolefin polyethylene (PE) and polypropylene (PP)? A: Within the various plant forms of biological life, i.e., bacteria, actinomycetes, fungi and algae, polymer degradation is essentially nonexistent due to high molecular weight of the common […]

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The GMA Techline

October 1st, 2020

Moderated by George R. Koerner Puncture after NDT Q: I would like your opinion on the fate of punctures in the air channel leftover from nondestructive air channel tests (NDTs), specifically in regard to sealing the air channels to prevent leachate or water ingress. We are particularly concerned with this situation on a landfill cover […]

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The GMA Techline

August 1st, 2020

Seaming dissimilar geomembranes Q: I kindly request your technical support in the questions below: A nonpolyethylene geomembrane was used in phase 1 of the tailings dam waterproofing system of a gold mine. For the expansion (phase 2), the use of a high-density polyethylene (HDPE) geomembrane is being evaluated. How can the HDPE geomembrane join the bituminous […]

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The GMA Techline

June 1st, 2020

Moderated by George R. Koerner Minimum sediment thickness Q: We are going to construct some evaporation ponds on existing sediment on top of a Hypalon geomembrane. The sediment looks to be predominantly fine. The subgrade condition below the liner is not known for sure. In such conditions, can you recommend a minimum sediment thickness that […]

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GMA history, Part 2

June 1st, 2020

During the Geosynthetics CASE STUDIES Conference in March in North Charleston, S.C., a few of the past Geosynthetic Materials Association (GMA) leaders had an opportunity to address the gathering and recall their personal experiences and achievements when they chaired the GMA executive council. This is the second installment of the history of GMA.  Beginning in […]

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GMA history and happenings

April 1st, 2020

By Andrew Aho Throughout the history of geosynthetics, leaders have emerged who have significantly affected the growth of the industry in North America. During the Geosynthetics CASE STUDIES Conference in March in North Charleston, S.C., a few of the Geosynthetic Materials Association (GMA) leaders had an opportunity to address the gathering and recall their personal […]

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The GMA Techline

April 1st, 2020

Moderated by George R. Koerner and Y. “Grace” Hsuan Welding Rod Q: This question is in regard to the welding rod intended for welding of geomembranes (both high-density polyethylene [HDPE] and linear low-density polyethylene [LLDPE]). Are there any GRI GM13- or GM17-based requirements for welding rods or are there any white papers or specifications? I […]

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The GMA Techline is 15 years old

February 1st, 2020

By Robert M. Koerner The GMA Techline was initiated on Sept. 1, 2004, as a free worldwide answer center for questions involving any, or all, aspects of geosynthetics. There were no constraints put on the questioners, or on the answers that were provided by the Geosynthetic Institute (GSI). To date, 3,500 Q and As have […]

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