What is the CSI code for geosynthetics?
August 1st, 2022
Q: What is the CSI code for geosynthetics? A: Originally founded in 1948, the Construction Specifications Institute (CSI) is a United States national association of more than 8,000 construction industry professionals who are experts in building construction and the materials. It is the founding institution for organizing and coding specifications related to construction projects. The […]
An open solicitation to work on development of a new GSI specification for EIA geomembrane
August 1st, 2022
GSI has a long history of writing specifications for geosynthetics. Like all engineered materials, geosynthetics are used in many applications and need general requirements for plans and specifications. When the NSF ceased servicing NSF #54 “Specification for Geomembranes” in 1991, The Geosynthetic Institute (GSI) was requested by its membership to continue the effort. With a […]
New GSI test method for resistance of conductive geosynthetics
June 1st, 2022
The Geosynthetic Institute (GSI) has a new test method for resistance measured across positions on conductive geosynthetics. Conductive geosynthetics contain an electrically charged backing (usually a thin layer of polyolefin with letdowns containing 20%–30% carbon black) that allows leaks to be detected in lined systems without the need for a conductive subgrade beneath the liner […]
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 […]
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 […]
EPDM geomembrane for a water application
February 1st, 2022
Q: We are looking at a life-cycle study for the usefulness of an ethylene propylene diene monomer (EPDM) geomembrane for a water conservation application. Request to kindly share the information for our study. Regards. A: An EPDM geomembrane is going to lie flat on the subgrade soil without wrinkles (no field-induced stress). Therefore, it will […]
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 […]
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 […]