Landfill trenches with geocomposites

June 1st, 2022

Q: I am wondering if you know of or can point me in the right direction in regard to determining viability of leachate disposal via spraying back onto the active face of a landfill. I have a landfill that has a few issues, and while, from a practical sense, we have had some success with […]

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Adding graphene to geosynthetics

June 1st, 2022

Q: I have some commercial application questions in the field of geosynthetics. We manufacture graphene powders in the most sustainable way, and it allows us to supply graphene to manufacturers much more economically. As you may have heard, graphene has wonderful material properties atomically to offer, and I am looking for opportunities to leverage its […]

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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 […]

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Welding HDPE geomembranes with biogas present

April 1st, 2022

Q: We are a Brazilian company specializing in biogas plants. We have built a big lagoon biodigester with a high-density polyethylene (HDPE) geomembrane cover. Now the cover is leaking liquid contained in the lagoon: We are organizing the repair procedure, and we would like to first investigate state-of-art practices and procedures for welding HDPE geomembranes […]

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NSF 61-certified HDPE geomembranes

April 1st, 2022

Q: Hi, we are looking for options for NSF 61-certified high-density polyethylene (HDPE) liners for installation in a potable water tank, 95th-percentile concentration of free chlorine in the tank is 1.2 ppm (1.2 mg/L). The current liner (60-mil [1.5-mm] textured HDPE, installed in 1999) is damaged and needs to be repaired or replaced. We are […]

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Impregnation of GCLs

April 1st, 2022

Q: We are confused with the term “impregnation” as it relates to seaming geosynthetic clay liners (GCLs). There are two types of impregnations: (1) Edge impregnation, and (2) complete nonwoven (cap layer) impregnation of GCLs. How does a manufacturer do this? A: The edge impregnation of GCLs (1) is done in the field by an […]

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GCL-GM geocomposite: Which end is up?

April 1st, 2022

Q: In a geosynthetic clay liner-geomembrane (GCL-GM) geocomposite, does it make any difference which side of the geocomposite is up: GM or clay? A: This is a very detailed question that is application specific. The following design details all need to be considered: Is the GCL-GM geocomposite used for a liner or a cover, is […]

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Calendared nonwoven geotextiles

April 1st, 2022

Q: What is the difference between normal nonwoven and calendared nonwoven (both needlepunched) geotextiles? Where can we use calendared nonwoven geotextiles? A: Calendared nonwoven geotextiles are passed between a set of heated rollers that applies normal pressure as a tertiary process of the production. This process increases the modulus, strength, tear resistance, puncture resistance and […]

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LCC curing effect on geogrids

April 1st, 2022

Q: Can you tell me whether modest warming of geogrids (e.g., due to heat generated by the curing of lightweight cellular concrete [LCC]) might impact the long-term strength or long-term modulus of geogrids? A: You need to know the maximum temperature due to the heat from hydration of the LCC. Most pozzolanic reaction temperatures (like […]

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High pH effects geogrids?

April 1st, 2022

Q: Can you tell me whether the high pH of curing portland cement (typically ~12.4) might have any impact on the long-term performance of geogrids? A: It depends on the geogrid and its formulation. There are three categories of geogrid: (1) punched and drawn (polyethylene [PE] uniaxial, polypropylene [PP] biaxial and triaxial), (2) strap (polyvinyl […]

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