TEXTILES.ORG
Geotextile filtration clogging resistance
February 1st, 2022
Q: I have a question about the Filter Criteria in the Federal Highway Administration (FHWA) procedure "Filter Performance and Design for Highway Drains" procedure, specifically the geotextile filtration clogging resistance equation 2-10. This seems to require a particularly large pore size; for example, if the D15 of the soil was for 70 microns, the minimum […]
Sewn versus welded seams
February 1st, 2022
Q: On your GMA Techline website list of sample questions and answers, 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 clay liner (GCL) overlap seams via eight methods. Can you share that study […]
Geosynthetics for pipe wrapping
February 1st, 2022
Q: I need impervious geosynthetics for pipe wrapping that will be placed within heavy clay. Do you have any suggestions? A: One wraps nonpolymeric pipes for many reasons. Below are some examples: Insulation (sound and thermal)Corrosion protectionWaterproofingImpact resistance Most wraps are tapes or mastics. Polyvinyl chloride (PVC), butyl rubber and bituminous wraps are common. A […]
Fusion-welded HDPE geomembrane patch
February 1st, 2022
Q: I need to make sure of what the minimum area is for a fusion-welded HDPE geomembrane patch with a 60-mil (1.5-mm) thickness 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)? Thank you […]
Electrical leak detection at depth
February 1st, 2022
Q: I am taking the opportunity to ask a question about the electrical leak detection (ELD) test for geomembranes: We have the area covered with silt from the past rainy season, and it is estimated to be about 5 feet (1.5 m) deep worst-case scenario. The liners in this area were not properly inspected and […]
ABS geosynthetics product types
February 1st, 2022
Q: Infrequently, I make a note of geosynthetic products manufactured using acrylonitrile butadiene styrene (ABS) (e.g., geogrid, binding line, a few molded specialty products). Can you provide a summary of most of the geosynthetic product types using ABS, as well as the general benefits and limitations of ABS geosynthetics? A: Thank you for your GMA […]
Residual strength of a geosynthetic clay liner
October 1st, 2021
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 […]
Measuring strain in geosynthetics
October 1st, 2021
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. A: This question arises often when comparing ISO 527/ASTM D638 and ASTM D6693 results. The former requires an extensometer, where the latter utilizes crosshead deflection and assumes gauge lengths. This discussion […]
Repeatability and reproducibility in geosynthetics
October 1st, 2021
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? A: One wishes to have the repeatability and reproducibility as “low” as possible, […]
Heat resistance of geomembranes
October 1st, 2021
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? A: The answer to this depends very much on the formulation from which […]