Sewn versus welded seams

February 1, 2022  |  Q&A: GMA Techline

Q: On your website list of sample questions and answers (https://geosynthetics.ifai.com/programs/gma-techline), a question is asked about a recommendation for sewn versus welded seams for geotextiles. Bob Koerner answered this question by stating that you have done a study for joining geosynthetic c…
EPDM geomembrane for a water application

February 1, 2022  |  Q&A: GMA Techline

Q: We are looking at a life-cycle study for the usefulness of an ethylene propylene diene monomer (EPDM) based geosynthetic liner for a water conservation application. Request to kindly share the information for our study. Regards.
Geosynthetics for pipe wrapping

February 1, 2022  |  Q&A: GMA Techline

Q: I need an impervious geosynthetic to wrap a pipe that will be placed within a heavy clay. Do you have any suggestions?
Fusion-welded HDPE geomembrane patch

February 1, 2022  |  Q&A: GMA Techline

Q: I need to make sure of what the minimum area is for an HDPE geomembrane with a 60-mil (1.5-mm) thickness patch that should be fusion welded instead of extrusion welded. Also, when does one need to replace a panel that is damaged (i.e., the percent of damage allowed to be repaired)?
Heat resistance of geomembranes

October 1, 2021  |  Q&A: GMA Techline

Q: We have a question in regard to the heat resistance of geomembranes. We are interested in paving a road over a geomembrane with hot mix asphalt and want to know if the geomembrane will continue to function as a moisture barrier?
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?
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.
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…
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…
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?