00350.01 293 Section 00350 - Geosynthetic Installation
Description
00350.00Scope - This Work consists of furnishing and placing G eosynthetics in drains, under
embankments, for embankment reinforcement, under riprap, Buttresses, inlays, shear keys, over Roadbed Subgrades, and beneath Pavement overlays as shown or directed.
00350.01Definitions - Terms not defined in this Subsection may be found in ASTM D123 and
ASTM D4439. If there is a conflict, definitions in this Subsection take precedence.
Cross -Machine Direction - The direction in th e plane of the fabric perpendicular to the direction of manufacture.
Drainage Geotextile - For installation as a filter in subsurface drains or other drainage locations.
Embankment Geotextile - Embankment Geotextile is used as a reinforcement within embankments and as a separation and reinforcement under embankments.
Geosynthetics - A planar product manufactured from polymeric material used with Soil, Rock , earth or other geotechnical, engineering related material as an integral part of a man-made product, Structure or system. Geogrid - A geosynthetic used for reinforcement which is formed by a regular network of tensile elements with apertures of sufficient size to allow strike-through of surrounding Soil , Rock or other geotechnical material. Geotextile - A permeable geosynthetic comprised solely of textiles.
• Nonwoven Geotextile - A textile produced by bonding or interlocking of fibers by mechanical, heat or chemical means.
• Woven Geotextile - A textile comprising of two or more sets of filaments or yarns interlaced in such a way that they result in a uniform pattern.
Machine Direction - The direction in the plane of the fabric parallel to the direction of manufacture. Pavement Overlay Geotextile - For installation as a reinforcement beneath an asphalt concrete overlay.
Riprap Geotextile - Riprap Geotextile is used as a filter and separator behind or beneath riprap, Buttresses, inlays, shear keys and erosion control applications.
Roll - Unit of continuous geosynthetic without transvers e seams as furnished by the manufacturer. Roll sizes may vary between manufacturers and types of G eosynthetics.
Roll Values:
• Average Roll Value - The Average Roll Value for each property is determined by testing a representative number of samples in a Roll according to the test methods specified in
• Minimum Average Roll Value - The Minimum Average Roll value for each property is the mean of the A verage Roll Values for all Rolls tested minus two standard deviations, all as determined by the manufacturer. The Minimum Average Roll Value for each property is determined by 00350.10 294 testing a representative number of Rolls in a production run according to ASTM D4354 sampling procedures and the test methods specified in Section 02320.
• Minimum Value - The Minimum Value is the specified value for each geosynthetic property that shall be met or exceeded by the manufac turer's Minimum Average Roll Value for the production run and, if sampled and tested by the Agency, by the Average Roll Value for any Roll. Seam Allowance - The minimum distance from the edge of a Geotextile to the stitch line nearest to that edge.
Seam Type - A designation relating to the essential characteristics of Geotextile positioning and rows of stitching in a specified sewn seam as shown.
Selvage - The finished edge of a G eotextile parallel to the Machine Direction.
Stitch Type - A designation relating to the essential characteristics of the interlacing of sewn threads in a specified seam as shown.
Subgrade Geotextile - Subgrade Geotextile is used as a separator and reinforcement on Subgrades and in other material separation applications. Ultraviolet Rays - Direct radiation from the sun during daylight hours, even on cloudy days.
Ultraviolet Stability - The ability of a geosynthetic to resist deterioration when exposed to UV radiation.
Materials
00350.10Materials - Furnish Materials meeting the requirements of Section 02320
Equipment
00350.20Field Seam Stitching Equipment - Use field seam stitching Equipment that provides an
acceptable lock -type stitch as recommended by the G eotextile manufacturer and approved by the Engineer.
00350.21Asphalt Distributor - Design, equip, maintain, and operate the asphalt distributor
according to 00730.22.
Construction
00350.40General - Provide geosynthetic as furnished by the manufacturer and protect against
damage and deteriorati on. Prevent excessive mud, wet concrete, epoxy and like materials from coming in contact with the geosynthetic. Store all Geosynthetics in a dry place and off the ground at all times according to ASTM D4873. Cover all G eosynthetics with a dark protective covering when received. The geosynthetic will be rejected for use if the Engineer determines it has defects or deterioration, or has been damaged.
00350.41 295 00350.41 Geotextile Installation Requirements:
free of obstructions, depressions and debris unless otherwise directed. Do not drag the Geotextile on the ground or mishandle in any way. Loosely place the G eotextile without wrinkles so placement of the overlying Material will not tear the G eotextile. Lap or sew the G eotextile at the ends and sides of adjoining sheets as specified.
Lap the upper sheets over the lower sheets. When the Geotextile is placed on a Slope steeper than 6V:1H, securely anchor the laps to the ground surface with pins or stakes as necessary to prevent the slippage and tearing of the Geotextile. Start placement of fill M aterial on the Geotextile at the toe of the slope and proceed upwards.
will flow, the G eotextile may be placed with the Machine Direction parallel to the direction of water flow instead of the placement direction specified in 00350.41(a)(1)(b). Overlap sheets so the upstream sheet is placed over the top of the downstream sheet. Adequately secure the Geotextile to prevent slippage. As the G eotextile is placed under water, place the backfill Material on it to the required thickness. Do not place G eotextile more than 50 feet ahead of the specified cover Material .
Application Minimum Overlap Requirements (Inch) Drains 12 Embankment Stabilization 24 Pavement Overlays * Riprap and Rock Buttresses 24 Roadbed Subgrade Stabilization 24 * Use sufficient overlap to ensure closure, but not more than 6 inches. If the Engineer determines the specified overlap is not sufficient, increase the overlap to provide adequate coverage or, if approved by the Engineer, sew the G eotextile together in the field. If field-sewn, the provisions of 00350.20 and 00350.41(a)(3) apply.
Sew field seams with polymeric thread consisting of polypropylene, polyester or kevlar, and as resistant to deterioration as the G eotextile being sewn. Use a color of thread that contrasts with the G eotextile being sewn so the stitches are exposed for inspection when the G eotextile is placed. Seams shall meet the testing requirements of 02320.11(b).
as shown. The two rows of stitching shall be 1/2 inch apart with a tolerance of plus or minus 1/4 inch and not cross except for restitching. 00350.41 296
the edge of G eotextile to the nearest stitching) is:
Seam Type (See Plans) Minimum Seam Allowance (Inch) Flat or Prayer Seam, Type SSa -1 1 1/2 "J" Seam, Type SSn -1 1 Butterfly -folded Seam, Type SSd -1 1
and stitch to be used. If the Contractor does not obtain and provide the foregoing technical information use a "J" seam with at least three stitches per 1 inch. The flat, or prayer, seam may be used for repair of damaged in-place Geotextile.
contamination by surface runoff and construction activities.
Traffic or construction Equipment is not allowed directly on the Geotextile except as authorized in 00350.41(f)(5) or as directed. During installation, cover the G eotextile with specified cover M aterial as soon as possible. Do not leave in uncovered condition for more than 5 Days. Place cover M aterial on the G eotextile in such a manner that the G eotextile is not torn, punctured or shifted. Use a minimum 6-inch thick cover layer or twice the maximum Aggregate size, whichever is thicker. Do not end-dump cover M aterial directly on G eotextiles other than R iprap Geotextile. Limit construction vehicles in size and weight so rutting in the initial layer above the G eotextile is not more than 3 inches deep or half the layer thickness, whichever is lesser. Do not turn vehicles on the first layer.
during construction at no cost to the Agency. Repair by placing a patch of the specified Geotextile over the affected area. Overlap the existing G eotextile with the patch according to 00350.41(a)(1) . Where G eotextile seams are required to be sewn, repair any damaged sheet by sewing unless otherwise indicated on the Plans or Special Provisions, or as directed.
shown to loosely conform to the shape of the trench with no wrinkles or folds.
Place the G eotextile layers so the G eotextile Machine Direction i s transverse to the embankment centerline. Spread the Geotextile so all slack and wrinkles are eliminated. Construct embankment in uniform layers according to Section 00330.
keys and erosion control applications according to the details shown. Demonstrate to the satisfaction of the Engineer that the combination of the Rock -fill drop height and the thickness of any Aggregate cushion, when specified or required, is adequate to prevent puncturing or damaging the Geotextile when placing the riprap or stone embankment Material . If an Aggregate cushion is used, place according to 00350.41(a)(4). In addition, the following limits apply: 00350.41 297 Maximum Drop Height (Feet) Size of Rock Onto Geotextile Material Onto an Aggregate Cushion Blanket Greater than 200 pounds 0 3 200 pounds or less 3 3
After placing the riprap, backfill all voids in the riprap face so the Geotextile is completely covered and not visible.
to Section 00330. Correct Geotextile failures, as evidenced by Soil pumping or Roadbed distortion, by removing any covering Material in the affected area and placing a G eotextile patch on the exposed G eotextile according to 00350.41(a)(5) . Cover the patch with the specified cover M aterial and com pact before proceeding.
• Surface preparation • Sealant application • Geotextile placement • Overlay placement
of 00745.40 are met, as appropriate, except the minimum air temperature shall be 50 °F for paving grade asphalt seala nt placement and 60 °F for asphalt emulsion sealant placement.
according to 00730.42 and the following:
• Clean and fill cracks exceeding 1/8 inch width with a bituminous crack filler from the QPL. • Repair minor irregularities or depressions as directed. • Allow crack filling Material to cure before placing Geotextile. • Where the Pavement is severely cracked, rutted, deformed or otherwise distressed, place a Leveling Course as directed instead of extensive surface preparation.
may be used as approved. Do not use cutbacks or emulsions that contain solvents.
Uniformly spray the asphalt sealant at normal application temperature by means of a pressure distributor conforming to 00350.21 on the prepared dry Pavement surface. Apply at the rate of 0.20 - 0.30 gallon per square yard, or as recommended by the G eotextile manufacturer or as directed.
If using emulsions, increase the application rate 50 percent or as directed. Some underlying surfaces may require a higher application rate. Within street intersections, on steep grades or in other zones where vehicle speed changes are commonplace, reduce the normal application rate by 20 percent or as directed. 00350.42 298 The target width of the sealant application shall be the Geotextile width plus 6 inches. Apply the sealant only as far in advance of the G eotextile installation as appropriate to ensure a tacky surface at the time of G eotextile placement. Place the G eotextile the same Day as the sealant. Do not allow traffic on the sealant. Clean excess asphalt from the road surface.
laydown Equipment capable of providing a smooth installation with a minimum amount of wrinkling or folding from the water (break) before placing the G eotextile.
Slit wrinkles or folds exceeding 1 inch and lay flat. Shingle- lap not more than 6 inches in the direction of t he paving. Broom or squeegee to smooth the Geotextile and pneumatic roll to maximize Geotextile contact with the Pavement surface. Additional hand- placed sealant Material may be required at laps as determined.
Limit traffic to necessary construction Equ ipment and emergency vehicles on the Geotextile before and during paving unless otherwise directed. Turn the paver and other vehicles gradually. Keep turning to a minimum to avoid Geotextile movement and damage. Avoid abrupt starts and stops.
sealant that bleeds through the Geotextile. Do not windrow asphalt concrete Material on the Geotextile ahead of the paving machine. Do not use an asphalt concrete M aterial pickup machine.
00350.42Subgrade Reinforcement Geogrid Installation Requirements :
and as follows:
Orient the G eogrid Rolls parallel to the R oadway centerline. Unroll the G eogrid in the same direction the cover Material will be placed. If the G eogrid shifts or becomes misaligned, realign it and anchor it according to the manufac turer's recommendations.
direction the cover Material is placed with the preceding layer lapped on top of the following layer.
Drive tracked Equipment on the Geogrid only after placing a minimum of 6 inches of cover Material on top of the G eogrid. Do not turn or make sudden stops or starts on the Geogrid or cover M ateria l.
During installation cover the Geogrid with cover M aterial as soon as possible. Do not leave uncovered for more than 5 Calendar Days.
recommendations at no cost to the Agency.
00350.90 299 Measurement
00350.80Measurement - The quantities of each geosynthetic installation will be measured on the
area basis along the lines and grades of the surface area actually covered as shown or as required, except for drainage applications.
The quantities of Drainage Geotextile will be measured on the area basis, computed by multiplying the length of the trench where G eotextile is used by the perimeter of the trench as determined from the Neat Lines shown, or as directed.
Payment
00350.90Payment - The accepted quantities of Geosynthetics will be paid for at the Contract unit
price, per unit of measurement, for the following items:
Pay Item Unit of Measurement
In items (a) and (c), the type of G eotextile will be i nserted in the blank.
Item (e) includes preparation Work , sealant, and Geotextile.
Payment will be payment in full for furnishing and placing all Materials, and for furnishing all Equipment , labor, and Incidentals necessary to complete the Work as specified.
No separate or additional payment will be made for constructing laps, seams, joints, or patches unless the Engineer orders additional amounts over the minimum. For laps wider than the minimum or specified wi dth, payment will be made for the added lap width at the Contract unit price.