Article 1 — Description
Use geogrid to reinforce flexible bas e placed on embankment material. Geogrid consists of a synthetic planar structure formed by a regular network of integrally connected polymeric tensile elements with apertures designed to interlock with the base and the underlying material.
Article 2 — Materials
Furni sh geogrid of the type shown on the plans meeting the requirements of DMS -6240 , “Geogrid for Base/Embankment Reinforcement.” When directed, randomly select a roll from those delivered to the project and sample a piece of geogrid from the roll in accordance with Tex-735-I . Do not sample from an area of the roll that is damaged or distorted. The Engineer must witness the sampling. The Materials and Tests Division (MTD) will test the geogrid sample to determine whether it meets the material requirements of DMS -6240 . When test results fail to meet any of the minimum requirements, the Engineer may reject the roll and may randomly select an additional roll to sample and test. If the additional sample fails to meet any of the material requirements, the Engineer may reject the entire quantity of rolls represented by the samples tested.
2.1 Packaging . Package geogrid in rolls of the length and width shown on the plans or as approved. Package
each roll in one continuous piece in a suitable sheath, wrapper, or container to protect the geogrid from damage due to ultraviolet light, moisture, storage, and handling.
2.2 Identification . Identify each roll with a tag or label securely affixed to the outside of one end of the roll. List
the following information on the label: manufacturer’s roll number, manufacturer’s lot or control number, name of manufacturer and supplier, style or catalog description of product, and roll width and length.
Article 3 — Construction
Install geogrid in accordance with the lines and grades as shown on the plans. Do not operate tracked construction equipment on the geogrid until a minimum cover of 6 in. of flexible base backfill material is placed on the geogrid. Install the geogrid to avoid any deformation or damage to the underlying, compacted material below the geogrid. When the underlying, compacted material below the geogrid is damaged during installation, correct all areas to the satisfaction of the Engineer.
3.1 Geogrid Placement . Orient the geogrid length as unrolled parallel to the direction of roadway. Overlap
geogrid sections as shown on the plans or as directed. Use plastic zip- ties at overlap joints or as directed. When placing geogrid around corners, cutting and diagonal lapping may be required. Pin geogrid at the beginning of the backfill section as directed. Keep the geogrid taut and flat throughout backfilling, but not restrained from stretching or flattening. Use a track loader to place the flexible base material by cascading it onto the geogrid to a minimum depth of 6 in. Spread, shape, and use ordinary compaction to compact the flexible base material into a uniform layer. Avoid direct contact by equipment with the geogrid. When approved, rubber -tired equipment may be operated directly on the geogrid. When approved, operate the rubber -tired equipment at a maximum of 172 5 mph, do not turn tires on the geogrid, do not make sudden stops and starts on the geogrid, and do not distort the geogrid to create excessive deformation waves. Correct areas with distorted and excessive deformation waves to the satisfaction of the Engineer. When directed by the Engineer, adjust the geogrid installation and construction methods to minimize any distortion and deformation waves.
3.1.1 Longitudinal Joints . Overlap longitudinal joints by a minimum of 1 ft. Space longitudinal zip- ties 10– 20 ft. or
as directed.
3.1.2 Transverse Joints. Overlap transverse joints by a minimum of 1 ft. Space transverse zip-ties 4 –5 ft. or as
directed.
3.2 Damage Repair . Remove and replace Contractor- damaged or excessively deformed areas as directed at no
additional cost to the Department. Lap repair areas a minimum of 3 ft. in all directions. Tie each side of repair grid in at least three locations, but do not exceed normal construction spacing. The tie spacing for odd shapes will be as directed. Repair excessively deformed materials underlying the grid as directed.
Article 4 — Measurement
Geogrid base reinforcement will be measured by the square yard of roadway placement as shown on the plans with no allowance for overlapping at transverse and longitudinal joints.
Article 5 — Payment
The work performed and materials furnished in accordance with this Item and measured as provided under “Measurement” will be paid for at the unit bid price for “Geogrid Base Reinforcement” of the type specified. This price is full compensation for furnishing, preparing, hauling, and placing materials, including labor, materials, freight, tools, equipment, and incidentals.