6-46 surface treatment. This work includes subgrade preparation and placing and compacting Granular Borrow to the subgrade elevation.
614.02 Submittals Submittals shall comply with MaineDOT Secti on 105-General
Scope of Work. All information shall be submitted to the Reside nt thirty (30) days prior to the Geocell Slope Protection System installation.
A.Product Data. Submit manufacturer’s product data. B. Supplier Design. Submit manufacturer’s project-specific de sign recommendations or engineering design for cell size, stake anchor length and stake anchor spacing. The project specific design shall be prepared, checked, and sealed by a Pro fessional Engineer licensed in the State of Maine.
C.Shop Drawings. Submit manufacturer’s Shop Drawings includi ng section layout, direction of expansion, and anchor stake locations. The Shop Dr awings shall be sealed by a Professional Engineer licensed in the State of Maine.
D.Samples. Submit manufacturer’s samples of geocell sections , anchors, and end caps.
E.Material Certification. Submit manufacturer certification of polyethylene used to make geocell material including percentage of carbon black, pol yethylene density, and environmental stress crack resistance (ESCR).
614.03 Materials Materials for the Geocell Slope Protection S ystem shall meet the
requirements of the following sections: 614.031 Geocell Sections The geocell sections shall be a poly ethylene sheet strip assembly connected by a series of offset, full depth, ultrasoni c welded seams aligned perpendicular to the longitudinal axis of the strips, which, wh en expanded, form walls of flexible 3-dimensional, cellular slope protection confinement s ystem. The geocell material shall be manufactured by Presto Products Company, Appleton, Wis consin, Webtec Geosynthetics, Charlotte, North Carolina, or an approved equal. Sections shall be in conformance with manufacturers design recommendations or engine ering design for this project.
1.Geocell base material The geocell material shall be polyethylene stabilized with blac k carbon, with the following properties:
a.Density, ASTM D 1505: 58-60 pcf. b. Environmental stress crack resistance (ESCR) ASTM D 1693: 30 00 hours.
c.Ultraviolet light stabilization: carbon black. d. Carbon Black Content: 1.5 t o 2 percent by weight, through th e addition of a carrier with a certified carbon black content.
e.Homogeneously distributed through material. 6-47
2.Geocell Strip Properties and Assembly
a.Perforated Strip/Geocell: i Strip sheet thickness, ASTM D 5199: 50 mil minus 5%, plus 10%. Determine thickness in the flat before surface disruption. ii Sheet thickness: 60 mil +/- 6 mil. iii Polyethylene Strips: Perforated with horizontal rows of 0. 40 in diameter holes. iv Perforation Within Each Row: 0.65 to 0.75 in on center. v Horizontal Rows: staggered and separated 0.50 in relative to hole centers. vi Edge of strip nearest edge of perforation: 0.24 in minimum. vii Centerline of spot welds to nearest edge of perforation: 0. 70 in minimum.
b.Assembly of Geocell sections: i Fabricated using strips of sheet polyethylene each with a l ength of 12 ft and a width equal to cell depth. ii Connect strips using full-depth, ultrasonic spot-welds alig n perpendicular to longitudinal axis of strip. iii Ultrasonic weld melt-pool width: 1.0 in maximum.
3.Geocell Properties a. Individual Cells: Uniform in shape and size when expanded. Over- or under- expansion of uniform individual cells will be allowed on curved slopes.
b.Individual Cell Dimensions: i Length: 8.8 in +/- 10% ii Width: 10.2 in +/- 10% iii Nominal area 44.8 sq in +/- 1% iv Nominal depth: 4 in
4.Geocell Seam Strength Tests a. The seams for geocell sections shall consist of 2 carbon-bla ck stabilized strips welded together.
b.Short Term Seam Peel Strength Test:
i.Cell Seam Strength: Uniform over full depth of cell. ii. Minimum seam peel strength: 320 lbf for 4 in depth.
c.Long Term Seam Peel Strength Test: i Conditions: Minimum of 168 hours (7 days) in a temperature-c ontrolled environment that undergoes change on a 1-hour cycle from room temperature to 130º F. ii Room temperature: ASTM E 41. iii Test Samples: Weld two 4 in wide strips together. iv Test: Test sample consisting of 2 carbon black stabilized st rips shall support a 160 lb load for the test period. 6-48 614.032 Anchoring Components The anchoring system shall consi st of straight No. 4 steel reinforcing rods with an A TRA clip, or an approved equal, as end cap. Length shall be as specified in the manufacturer’s recommendations or the proje ct-specific design. 614.033 Granular Borrow Granular Borrow shall meet the requir ements of MaineDOT Section 703.19 - Granular Borrow, Material for Embankment Const ruction. 614.034 Geocell Infill Material Geo cell infill material shall be as specified in the project-specific design or as shown on the Plans and shall meet the requirements of the following specifications: L o a m 615.07 D i r t y B o r r o w 615.10 Aggregate for Crushed Stone Surface 703.12 614.035 Surface Treatment For geocell slopes with Loam infill , the surface treatment shall consist of seed and an erosion control blanket. The seed shall meet the requirements MaineDOT Section 618-Seeding, Method Number 2, or as indicated on the project-specific design, Plans and Notes. The erosion control blanket shall mee t the requirements of MaineDOT Section 613-Erosion Cont rol Blanket. When infill othe r than loam is specified, the surface treatment shall be as indicated on the project-spec ific design, Plans or details.
614.04 Construction Requirements The Geocell Slope Protection System shall have the
following construction requirements:
A.Subgrade Preparation.
1.Prepare the subgrade by removing the all existing vegetation and loose surficial soils from the slope.
2.Excavate and the slope section as needed. 3. Place, compact, and shape Granular Borrow as needed, so that when placed the top of installed geocell section is flush with or slightly lower that the final grade as indicated on the Plans.
4.Install non-woven erosion control geotextile underlayer, if required, on the prepared surface, ensuring required overlaps are maintained and outer ed ge of geotextile are buried a minimum of 6 in. below grade.
B.Placement and Anchoring.
1.Anchor geocell sections at the crest of the slope or as per manufacturer’s recommendations. Use type of anchor and frequency of anchoring as indicated on the shop drawings.
2.Expand geocell sections down slope. Confirm each geocell se ction is expanded uniformly to required dimensions and outer cells of each layer are correctly aligned.
3.Interleaf edges of adjacent sections. Ensure that the upper surface of adjoining geocell sections are flush at the joint and adjoining cells are fully anchored. Anchor with specified anchors in prescribed pattern throughout the slo pe surface.
Source: Maine Standard Specifications for Road and Bridge Construction, 2020 Edition. Pages 516–518 of 817.