Enhanced moisture management of pavement systems through capillary suction

June 1, 2020

By René B. Laprade and John M. Lostumbo Moisture within pavement layers is a principal cause of pavement deterioration (Cedergren 1994, Christopher and McGuffey 1997, Henry and Holtz 2001). Specific problems associated with moisture include (1) reduction in pavement strength caused by excess water in the base course layers and/or the subgrade soils, (2) shrinking …

Assessment of condition of an uncovered geosynthetic landfill bottom liner system

By James L. Hanson and Nazlı Yeşiller Composite liner systems consisting of geomembranes (GMs) placed over geosynthetic clay liners (GCLs) commonly are used for containment applications. Such systems are used in base liners for ponds, reservoirs, basins and canals, and bottom and cover liner systems for landfill facilities. Even though the use of GCL-GM composites …

The GMA Techline

Moderated by George R. Koerner Minimum sediment thickness Q: We are going to construct some evaporation ponds on existing sediment on top of a Hypalon geomembrane. The sediment looks to be predominantly fine. The subgrade condition below the liner is not known for sure. In such conditions, can you recommend a minimum sediment thickness that …

High-strength geocell and geogrid hybrid reinforcement

Compressor station gravel pad on soft subgrade By Sanat Pokharel, Timothy Yii, Marc Breault and Meisam Norouzi Infrastructure development in natural resources rich Alberta, Canada, often encounters very soft ground conditions that pose several construction and sustainability challenges to transportation infrastructure, such as roads, rails and pipelines. As the conventional construction practices may not always …

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Geosynthetic strip MSE wall at Point Defiance Marina

April 1, 2020

By Paul C. Frankenberger and Robert Lozano  This article will focus on a geosynthetic strip mechanically stabilized earth (MSE) wall case study using discrete geosynthetic strips with large precast facing panels (Figure 1), an innovation of the original MSE invention. The system is the Highway Innovative Technology Evaluation Center/National Transportation Product Evaluation Program reviewed GeoMega …

The GMA Techline

Moderated by George R. Koerner and Y. “Grace” Hsuan Welding Rod Q: This question is in regard to the welding rod intended for welding of geomembranes (both high-density polyethylene [HDPE] and linear low-density polyethylene [LLDPE]). Are there any GRI GM13- or GM17-based requirements for welding rods or are there any white papers or specifications? I …

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Construction water flow dynamics of the leak detection layer

By Abigail Gilson-Beck and Larry Shilling The double-lined containment facility featuring a leak detection system (LDS) is the most accurate way of assessing leakage through a primary geomembrane (Bonaparte and Gross 1992). This type of system also represents the gold standard for environmental protection, since leakage through the primary liner is collected and removed so …

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CSPE performance and history in long-term potable water storage applications

By Brian Fraser, Steven Roades, Mike Neal and Alex Gersch Chlorosulfonated polyethylene (CSPE) is a synthetic rubber-based material manufactured by a calendaring process into multiple layers and combines with a polyester reinforcement fabric for additional strength. Hypalon is a DuPont trademark for CSPE synthetic rubber (CSM) noted for its resistance to chemicals, temperature extremes and …

International Achievement Awards

Recognizing design excellence in geosynthetics The International Achievement Awards, sponsored by the Industrial Fabrics Association International (IFAI), recognize innovation, technical skill and design excellence in geosynthetic applications.  The awards are an annual competition promoting awareness of the specialty fabrics used in thousands of products and applications ranging in size and shape. For more than 70 …

The GMA Techline

February 1, 2020

Moderated by George R. Koerner and Y. “Grace” Hsuan DARCIAN PERMEABILITY Q: I am aware of the section in your book regarding geomembrane “permeability” and get from it that it aims to calculate an equivalent Darcian permeability using vapor diffusion via Fick’s law. Can one use the derived permeability then when calculating flow using Darcy’s …