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Classifying geotextiles

April 1, 2008

From the GMA Techline Subject: Classifying geotextiles — What is a “Class A” geotextile? (Ron, Maryland) Reply: I don’t know, but it sounds pretty good! I suspect that it comes from a state specification where product values are listed in an ascending or descending order, such as Class A, B, C, etc. or Class 1, …

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Transmissivity: An ambiguous contradiction

February 1, 2008

By Richard Lacey, TRI Environmental Introduction Specifying the transmissivity of a drainage product seems straightforward. There are only two approaches defined in the governing test method. One is to specify the required transmissivity, while the other is to specify the required in-plane flow rate. Of course, the specification must also include all of the parameters …

ASTM geosynthetics committees developing proposed new standards

October 1, 2007

Three subcommittees of ASTM International Committee D35 on Geosynthetics are currently developing several proposed new standards. The topics covered in the following proposed standards are geosynthetic clay liners, geomembranes, and the development of a mechanistic-empirical design guide for pavements. Committee D35 will meet Jan. 30-Feb. 1, 2008, at the January Committee Week in Tampa, Fla. …

Background and most recent GRI standards

August 1, 2007

By Bob Koerner In the 1980s, while supervising graduate research students in their geosynthetics theses topics, the issue of writing generic and standardized procedures arose in this (quite new at the time) geosynthetics field. Rob Swan generated our first formalized test methods with what became GRI-GG1: “Geogrid Rib Tensile Strength” (now ASTM D6637) and GRI-GG2: …

ASTM Vol. 04.13 Geosynthetics

June 1, 2007

Published: May, 2007 Volume 04.13 focuses on the mechanical, endurance, permeability, and filtration properties of geosynthetics. Applications such as roadway stabilization and repair, erosion control, geomembranes, soil drainage, and reinforcement, as well as hydraulic barriers composed primarily of man-made polymer sheets or spray applied systems are included. Also featured are standards on geosynthetic clay liners. …

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Product specification

From the GMA Techline Subject: Product specification We are proposing to stabilize a section of eroded riverbank with riprap. We would like to install a fabric beneath the riprap to hold the existing sandy soils in place. Can you give us a recommendation? The river is tidal and the area is exposed to full sun …

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Geotextile fabric

From the GMA Techline Subject: Geotextile fabric We are specifying geotextile fabric: between the soil media (in a raingarden) and the underlying stone that contains the underdrain pipe. between the sod and the underlying stone (water quality swale) that contains the underdrain pipe. the top, bottom, and sides of an infiltration trench (filled with VaDOT …

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AOS vs. EOS

From the GMA Techline Subject: AOS or EOS? What is the difference between AOS (Apparent Opening Size) and EOS (Equivalent Opening Size)? (Larry, Louisiana) Reply: The real answer is: “Not much.” Now let me answer your question. The U.S. Army Corps of Engineers developed AOS in 1972 on the basis of sieving glass beads through …

ASTM committee developing drain test

April 1, 2007

ASTM International Committee D35 on Geosynthetics is currently developing a proposed new standard that covers the test procedure for evaluating the effectiveness of prefabricated vertical drains to enhance the consolidation of soils under specified conditions. The proposed standard, WK13402-Test Method for Large Scale Consolidation Test for Prefabricated Vertical Drains, is under the jurisdiction of Subcommittee …

Membrane seams addressed in new ASTM standard

February 1, 2007

The increased use of geomembranes as barrier materials to restrict liquid migration created a need for a test method to evaluate the quality of geomembrane seams produced by tape methods. ASTM International Committee D35 on Geosynthetics has met this need with the approval of the new standard D 7272, Test Method for Determining the Integrity …