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?
Geotextile under articulated systems in slope armoring

June 1, 2021  |  Q&A: GMA Techline

Q: I have a question about the geotextile placed under articulated systems in slope armoring. Based on my understanding, a drainage layer is recommended between the geotextile and the armoring structure, but, since the armoring structure has some spaces in between the armoring blocks, won’t the pa…
Industry standard for wall drainage systems?

June 1, 2021  |  Q&A: GMA Techline

Q: I just watched your recorded video of mechanically stabilized earth (MSE) wall inspection. Thank you for the presentation; it was very informative. I do have a follow-up question for you. I was recently the site engineer for a precast panel MSE wall and now have the opportunity to inspect constru…
GCLs in cold temperatures

June 1, 2021  |  Q&A: GMA Techline

Q: I am working on supporting a guide (independent) on what to consider when geosynthetic clay liners (GCLs) are installed in minus temperature regions (e.g., –4˚F [–20˚C]). There is not much published on this, especially independently.
Useful service life of nonwoven geosynthetics

June 1, 2021  |  Q&A: GMA Techline

Q: Where can I find literature on the useful service life of nonwoven geosynthetic fabrics installed in soils? Thank you.
Anchors, tie-rods and whalers

April 1, 2021  |  Q&A: GMA Techline

Q: We are having issues related to obstructions in the reinforced zone of our mechanically stabilized earth (MSE) retaining walls. In the first case, there is a rock outcrop that is limiting the length of the geogrid reinforcement. In the second case, we have a drop-down inlet structure to divert st…
Geomembranes for reinforcement?

April 1, 2021  |  Q&A: GMA Techline

Q: We are using Robert Koerner’s Designing with Geosynthetics to calculate the required thickness of a geomembrane.
Installing a geomembrane low to high gradient?

April 1, 2021  |  Q&A: GMA Techline

Q: We are a large liner installation firm that has been asked to install a geomembrane liner from low gradient to high gradient. Is this the new normal?
GRI-GM19 peel specification

April 1, 2021  |  Q&A: GMA Techline

Q: Our liner system is a double composite and along a western tie-in. We need to extrusion-weld the secondary 60-mil (1.5-mm) HDPE (new cell) to an existing secondary 40-mil (1-mm) HDPE (old cell), and the state is continuing to have issues with the fact that we are using the 40-mil (1-mm) GRI-GM19 …
Concrete interlayers

April 1, 2021  |  Q&A: GMA Techline

Q: We are interested in using a geotextile as an “unbonded concrete interlayer” over existing concrete pavement to float the new slab over deteriorated pavement, instead of a thin asphalt layer. Do you have any guidance for us in this regard?