217Geotextiles and Biaxial Geogrids

Geotextiles and Biaxial Geogrids

217.1DESCRIPTION

This section describes the requirements for furnishing and placing geotextile, a flexible or stiff polymer biaxial geogrid and stiff biaxial geogrid.

217.2MATERIALS

1 Provide materials in accordance with the following:

Materials Subsection

Geotextile 805.2 Biaxial Geogrids 805.4

217.3EQUIPMENT

217.3.1 Geotextiles

1 Meet the following equipment loads when placing and compacting material above a geotextile:

wheel load in pounds [N] and the resulting contact area in square inches [square meters].

217.4CONSTRUCTION

217.4.1 General

217.4.1.1 Geotextiles

1 Submit test results and certification by the manufacturer showing the geotextile performance relative to contract requirements. Submit a test sample 6 ft [2 m] long by the full width of the roll at least 14 calendar days before the use of any geotextile. Obtain this sample from a roll of geotextile that is on the project site. Make sure the sample is labeled with the product name, machine direction, lot and batch number, date of sampling, project number, and certification of compliance. If sewing is specified, submit

Geotextiles and Biaxial Geogrids SECTION 217

a seam sample 6 ft × 3 ft [2 m × 1 m] with the seam in the center and parallel to the 6- foot [2 m] length.

2 During shipment and storage, enclose geotextile in heavy-duty wrapping to provide protection from direct sunlight, ultraviolet rays, moisture, temperatures greater than 140 °F [60 °C], mud, dirt, dust, and debris. When storing outdoors, elevate the rolls, and protect them with a waterproof cover. Remove unprotected geotextile from the project.

217.4.1.2 Biaxial Geogrid

1 Submit to the engineer, for verification, a sample of the geogrid 2 ft [0.61m] long by 2 ft [0.61m] wide, with one factory edge, at least 14 calendar days prior to its intended use on the project. Label samples with the project number, the product name, the product manufacturer, machine direction and date of sampling. Take samples for testing from the same lot of composite material delivered to the project. Ensure the number of samples taken is in accordance with ASTM 4354 for the quantity of composite material produced for that lot. The engineer reserves the right to sample and test materials delivered to the project. Submit to the engineer test results and certification by the manufacturer showing the geogrid performance relative to requirements.

217.4.2 Installation

217.4.2.1 Geotextiles

1 Lap geotextile at least 24 in [600 mm] at ends and sides of adjoining sheets. When sheets are sewn together, ensure seam strength and efficiency properties in accordance with Subsection 805.2, Geotextile and Impermeable Plastic Membrane. Overlap seams 24 in [600 mm]. Leave seams exposed for ease of inspection.

2 Place gravel or other specified material on the geotextile so that it is not torn, punctured, or shifted. Limit pile heights of materials to prevent geotextile distortion. Repair tears or punctures by placing a patch of the same type of geotextile over the ruptured area and overlapping at least 3 ft [1 m] from the edge of any part of the rupture or by patching with sewn seams that meet strength requirements in accordance with Subsection 805.2, Geotextile and Impermeable Plastic Membrane.

3 With approval, pegs or pins may be used to fasten geotextile for embankment erosion control until the specified cover material has been placed. Install pegs or pins only at locations that are not detrimental to the finished product. Do not use pegs or pins for other types of installation.

4 Except when used for erosion control and silt fences, place cover material over the geotextile daily. No equipment will be allowed directly on the geotextiles.

5 Repair ruts exceeding 3 in [75 mm] by filling with additional cover material.

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217.4.2.2 Biaxial Geogrid

1 Overlap longitudinal and lateral joints at least 2.0 ft [0.61 m] to ensure continuity.

2 After preparation of the ground, place the geogrid as shown in the contract or as designated by the engineer.

Roll out geogrid along the road alignment in the direction of advancing construction. Place the beginning/end of each new roll beneath the previous roll. Taper the excavation at the be ginning and ending stations of the excavation to avoid creating an abrupt transition.

4 Ensure the cover material is back dumped and spread over the geogrid to avoid direct contact between equipment tires and geogrid. Maintain the minimum lift thickness at all times. No equipment will be allowed directly on the geogrid. As the cover material is being placed, hand tension the geogrid ahead of advancement of the cover material to ensure flat contact between the geogrid and the subgrade. Repair torn geogrid at no additional cost to the department. Make the repair by placing a piece of the same geogrid over the ruptured area and overlapping the existing geogrid a minimum of 2 f t [0.61 m] from the edge of any part of the rupture.

217.4.2.3 Foundation Stabilization

1 When using geotextiles or biaxial geogrids for stabilization:

4 in [100 mm] before installation. Ensure that the surface is free of objects that might tear or puncture the geotextile.

217.5MEASUREMENT and PAYMENT

217.5.1 General

1 The engineer will measure:

no allowance for overlaps.

exposed surface area with no allowance for overlaps.

Geotextiles and Biaxial Geogrids SECTION 217

2 The department will pay as follows:

Pay Item

Pay Unit Measure to the Nearest Pay to the Nearest Geotextile SY [m2] 0.1 ft [0.5 m] SY [m2] Biaxial Geogrid SY [m2] 0.1 ft [0.5 m] SY [m2] Biaxial Geogrid (STIFF) SY [m2] 0.1 ft [0.5 m] SY [m2]

217.5.2 Referenced Sections for Direct Payment

1 When specified, the engineer will measure and pay for cover material in accordance with Section 203, Excavation and Embankment.