Geocomp introduces bi-directional shear testing machine

August 24, 2018  |  News, Testing & Materials

Geocomp announced in August it has released an addition to the company’s series of fully-automated laboratory soil testing systems: a Bi-Directional Cyclic Direct Simple Shear (BDCDSS) machine. This table-top unit allows simple shear testing to be performed in two orthogonal horizontal directions …
GEOKON certified to ISO 9001:2015

June 14, 2018  |  News, Testing & Materials

GEOKON Inc., a manufacturer of geotechnical and structural instrumentation, announced in a prepared statement on June 13, 2018, that they have been certified under ISO 9001:2015 from both the American National Standards Institute (ANSI)/ANSI-ASQ National Accreditation Board (ANAB) in the U.S. and th…
Report from the North American Geosynthetics Society (NAGS)

April 1, 2015  |  News, Testing & Materials

By Bob Mackey ASTM Committee D35 on Geosynthetics The ASTM Committee D35 on Geosynthetics met in New Orleans, La., Jan. 28–30, 2015. There was significant progress within several of the D35 subcommittees as noted here: Subcommittee D35.03 on Permeability and Filtration The issue that generated a g…
Allowable stress on geonets based on laboratory creep tests

October 1, 2014  |  Testing & Materials

By Dhani Narejo and Sam Allen Introduction The first article in this three-part series presented compressive stress-strain behavior of several different geonet structures. The collapse, or rollover, does not occur for many types of geonets. In the absence of a rollover, the compression of geonets is…
Allowable stress on geonets based on laboratory creep tests

August 1, 2014  |  Testing & Materials

By Dhani Narejo and Sam Allen Introduction This article focuses on biplanar geonets to the extent of the possible tendency for the two sets of integrally joined ribs to roll over on one another while load is applied. The significance of such a rollover is a reduced transmissivity value as compared t…
Geosynthetics committee examines drainage issues

July 17, 2014  |  Testing & Materials

Proposed ASTM standard for stormwater catch basin filters. ASTM International in a July 17 press release announced a proposed new standard that will offer a means to reduce the impact of contaminated stormwater entering local drains. WK45326, Specification for Stormwater Catch Basin Filter, will aid…
Geonet structure, short-term stress/strain behavior, and creep test methods

June 1, 2014  |  Feature, Testing & Materials

Part 1: Allowable stress on geonets By Dhani Narejo and Sam Allen Introduction Several types of geonets are used in numerous applications worldwide. Examples of the types of geonets include biplanar, triplanar, spiked or profiled, cuspated, tubular, and three-dimensional (3-D) filament meshes (see F…
The influence of soil type on interface behavior under pullout conditions

June 1, 2014  |  Feature, Geogrids, Testing & Materials

Part 3: European experience in pullout tests By Nicola Moraci, Daniele Cazzuffi, Lidia Sarah Calvarano, Giuseppe Cardile, Domenico Gioffrè, and Piergiorgio Recalcati 1. Introduction The rapid increasing application of geosynthetics as reinforcement elements for earth structures requires a car…
Long-term pavement testing by FHWA

April 1, 2014  |  Testing & Materials

Contamination by subgrade soil causes deterioration in pavements from progressive loss of effective aggregate base thickness. Introduction A major deterioration factor in pavements is the progressive loss of effective aggregate base thickness because of contamination by subgrade soil. In the service…
Air-channel testing of thermally bonded flexible polypropylene geomembrane seams

April 1, 2013  |  Feature, Geomembranes, Testing & Materials

By Timothy D. Stark, Richard W. Thomas, and Thomas J. Dehlinl Introduction For more than a decade, thermal welding has proven to be an efficient and cost-effective procedure for field-seaming geomembranes. Thermal welding of polyvinyl chloride (PVC) geomembranes has allowed use of air-channel tests …