When you're constructing paved roads, nothing offers support like Fornit biaxial geogrids. Strong and durable, they reinforce, confine and separate unbound a ggregate base and subbase materials with unsurpassed performance. By distributing the loads over a wider area, Fornit geogrids dramatically increase the bearing capacity of subgrade soils. And they're ideal for unpaved roads and construction platforms over soft soils.

Manufactured with high strength polypropylene yarns, and coated for protection against both installation damage and exposure to ultraviolet rays, Fornit geogrids are made to last. That said, you need only review the physical properties to know the numbers speak for themselves. Manufactured by HUESKER which is ISO 9001 certified for the development, manufacture, sales and applications support of high quality geosynthetics reinforcement products, Fornit geogrids make the difference.

You'll find a unique and revolutionary combination of tensile reinforcement, confinement and separation make these geogrids a significantly better product.

Tensile Reinforcement

Fornit geogrids provide excellent tensile reinforcement to the aggregate base and subbase layers of both paved and unpaved roads. With a tensile element that distributes the applied loads over a greater area, Fornit geogrids reduce the bearing capacity requirement of underlying soils. In fact, pullout tests simulating roadway conditions prove Fornit geogrids mobilize their strength in soils with minimum displacement, offering superior tensile reinforcement.

Confinement

There's no question, to maintain the integrity of the roadway under repeated wheel loadings, Fornit geogrids are the answer. They provide interlocking of the aggregate to give you maximum confinement of the base course, and maintain the desired thickness by reducing lateral displacement. This increased confinement is demonstrated by interface shear strength tests.

Separation

Finally, Fornit geogrids are manufactured with an aperture size designed to optimally separate typical base course and finer subbase materials. The engineered aperture size enables interlock of the geogrid with the aggregate layer, yet still provides separation. The ribs create a superior support structure for the aggregate to interlock and bridge, reducing vertical deformation of the base layer. The results? A product that provides unparalleled geogrid separation along with tensile reinforcement and confinement.

HUESKER geogrids have been successfully used as tensile reinforcement in civil engineering applications for over three decades. With the development of Fornit, HUESKER has once again demonstrated its leadership in geogrid reinforcement by providing a product that reinforces, confines and separates. Developing a high performance biaxial geogrid requires the precise measurement of the tensile modulus. Fornit has been thoroughly tested in our state of the art laboratory facilities for research and quality control purposes.

In addition, HUESKER has conducted numerous geogrid/soil interaction tests in order to develop the most efficient biaxial geogrid reinforcement. These independent laboratory tests clearly show the Fornit's ability to generate its tensile strength in roadway applications. Geogrid pullout and direct shear tests help define the tensile reinforcement and aggregate confinement achieved with Fornit. Comparisons of these results with other base reinforcement products reveals the superiority of the Fornit biaxial geogrids.

Construction of roads using geogrid reinforcement requires a durable product. The Fornit geogrids were also tested in full scale field trials by an independent laboratory to document their ability to survive installation stresses. In all cases the Fornit 20 and Fornit 30 proved that the coated polypropylene yarns are capable of retaining a high percentage of their original strength under the most severe field conditions.

Because of its strength and durability Fornit 20 is typically used for most paved and unpaved base reinforcement projects. However, where more severe loads and conditions exist, Fornit 30 should be used. Fornit 30 is well suited for the more demanding reinforcement requirements with its higher tensile strength and greater resistance to installation damage.

HUESKER has manufactured geogrids that have stood the test of time. And Fornit geogrids prove that a commitment to quality engineering produces more than a great product, it produces results. For more information on Fornit, call HUESKER at (800) 942-9418. Or visit our website at www.HUESKER.com. And let us show you how the right engineering and testing can work for you.

1. SCOPE

1.1 This is a specification covering biaxial geogrids for use in base and subbase reinforcement of roadways. The function of the reinforcement in this application is to include a tensile member in the form of a geogrid beneath the unbound base or subbase with the intent of increasing the structural support capacity of that component of the roadway structure.

1.2 Base reinforcement is defined as a geogrid placed directly beneath the base course to improve service life, and/or obtain an equivalent performance with a reduced structural section. The potential mechanisms provided by the base reinforcement include lateral restraint, increased bearing capacity, and/or tensioned membrane effect. Base course in this specification is defined as the layer or layers of specified or selected unbound material of designed thickness placed on a subbase or a subgrade to support a surface course.

1.3 Subbase reinforcement is defined as a geogrid placed at the subgrade/subbase interface to provide support for the roadway structural section. The potential mechanisms provided by the subbase reinforcement include increased bearing capacity, lateral restraint, and/or tensioned membrane effect. Subbase in this specification is defined as the layer or layers of specified or selected material of designed thickness placed on a subgrade to support a base course.

2. REFERENCED DOCUMENTS

3. PHYSICAL AMD CHEMICAL REQUIREMEMTS

3.1 The geogrid reinforcement shall consist of polypropylene yarns with a protective polymeric coating. The yarns shall be formed into a stable network such that the geogrid ribs retain their dimensional stability relative to each other. The geogrid material shall be Type 1 or Type 2 as shown on the plans or as directed by the project Engineer. Type 1 and Type 2 geogrids shall conform to the physical requirements listed in Table 1.

4. CERTIFICATION

4.1 The Contractor shall provide to the Engineer a manufacturer's certificate stating the name of the manufacturer, product name, style number, lot number, chemical composition of the geogrid product and physical properties applicable to this specification.

4.2 The Manufacturer of the geogrid shall be ISO 9001 certified or shall submit documentation of an established and currently maintained quality control program for the facility at which the geogrid was produced.

5. SAMPLING, TESTING, AND ACCEPTANCE

5.1 For manufacturing quality control purposes, the geogrid shall be tested for tensile strength at a minimum of every 20,000 yds² (16,723 m²).

5.2 Geogrid delivered to the site shall be subject to sampling and testing to verify specification conformance. Sampling for conformance testing shall be in accordance with ASTM D 4354 and performed at the contractors expense. Conformance of the geogrid material shall be established in accordance with ASTM D 4759 and Table 1 minimum average roll value (MARV) physical properties.

6. DELIVERY, STORAGE AND HANDLING

6.1 Contractor shall inspect the geogrid rolls upon delivery to ensure that the proper material has been received. During all periods of shipment and storage, the geogrid shall be wrapped in a protective poly wrap and not exposed to temperatures exceeding 150°F (65°c).

6.2 General storage and handling of the geogrid rolls shall be in accordance with procedures identified in ASTM D 4873.

7. GEOGRID INSTALLATION AND BACKFILL

7.1 The subgrade material shall be prepared to the lines and grades shown on the construction drawings. Geogrid panels shall be laid at the proper elevation and orientation as shown on the project plans or as directed by the manufacturer. The geogrid shall be placed flat and free of wrinkles. The geogrid may be unrolled and placed by hand or with construction equipment that does not damage the materials. Correct placement and orientation of the geogrid shall be verified by the installer.

7.2 Adjacent geogrid panels shall be overlapped using the following guidelines:
where the subgrade CBR is greater than 3 the overlap shall be 0.5 ft (15 cm);
where the subgrade CBR is between 2 - 3 the overlap shall be 1.0 ft (30 cm);
where the subgrade CBR is between 1 - 2 the overlap shall be 1.5 ft (46 cm);
where the subgrade CBR is between 0.5 - 1.0 the overlap shall be 2.0 ft (61 cm);
where the subgrade CBR less than 0.5 the overlap shall be 3 - 4 ft (91 - 122 cm) or seamed. Minimum end to end overlap shall be 3.0 ft (91 cm).

7.3 Cover soils shall be placed, spread and compacted in such a manner that minimizes the development of wrinkles and/or movement of the geogrid. Fill material can be placed directly upon the geogrid. Geogrid should be covered with soil within 30 days of placement to protect against unnecessary exposure.

7.4 Tracked construction equipment shall not operate directly on the geogrid. A minimum fill thickness of six inches is required prior to operation of tracked vehicles over the geogrid. Turning of tracked vehicles should be kept to a minimum to prevent tracks from displacing the fill and damaging the geogrid. Place the fill material on the geogrid with a rubber-tire scraper, dump trucks, or front end loaders; or push fill material onto the geogrid with a dozer.

7.5 Rubber tire vehicles may be operated on top of the geogrid, however, sudden stops, excessive speed (over 15 mph), and sharp turns should be avoided. Any geogrid damaged during installation shall be repaired or replaced in accordance to the manufacturers recommendations.

8. MEASUREMENT AND PAYMENT

8.1 The geogrid shall be measured by the square yard placed. The accepted quantities shall be paid for at the contract unit price. Payment shall be full compensation for all labor, tools, and equipment necessary to satisfactorily complete the work.

Fornit Variable Mesh Size Fornit geogrids are manufactured with a variable mesh size across the 17' wide rolls. The geogrid apertures vary between the inner 15' of the roll width and the outer edges. This variable mesh size provides separation and reinforcement throughout the interior of the roll while maintaining continuity of tensile strength across geogrid overlaps.

Informations to applications:

Earthworks and foundations

Roads

Railways

Landfill

Industrial and contaminated land reclamation

Reports:

	Base Reinforcement with the biaxial Fornit® 30 - Special Operations Field - Hot Cargo / Airfield - Readiness, Hurlburt Field, Florida USA		158 KB
	Grand Lake Meadows - Route 102 to Route 695 Fredericton-Moncton Highway project New Brunswick, Canada
	U.S. Highway 45 project - Wisconsin Dot project No. 1602-03-70 - Langlade County, Wisconsin
	Keen Transport Company - Jimmy Deloach Parkway Savannah, Georgia
	FORNIT® 20 biaxial geogrid test section - Construction haul road Concord, North Carolina
	Bryan Station Road - Kentucky Department of Transporation Project Lexington, Kentucky

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