358 ALASKA 2020 SECTION 632
632-1.01 DESCRIPTION . Furnish and install geotextile paving fabric where shown on the Plans.
632-2.01 MATERIALS. Use materials that conform to the following:
Paving Fabric Subsection 729- 2.03 Emulsified Asphalt Subsection 702- 2.03
632-3.01 Constructio N Requirements.
1.Surface Preparation. Prepare the surface on which the fabric is to be placed as follows:
a.Remove excess asphalt material, loose aggregate, and other foreign materials from the surface.
b.Fill all potholes and cracks wider than 1/4 inch with emulsified asphalt (CSS -1) sand slurry.
2.Application of Sealant . Apply asphalt sealant (emulsified asphalt, tack coal) by distributor meeting all requirements set forth under Subsection 402- 3.02. Apply asphalt sealant uniformly at 0.20 to 0.30 gallons per square yard and at a temperat ure shown in Table 702- 1 or as recommended by the Paving Fabric manufacturer. Do not apply asphalt material on a wet surface or when the ambient air temperature is below 45 °F or when other conditions would prevent proper application.
3.Fabric Laydown Equipment . Use approved mechanical laydown equipment to place fabric.
4.Fabric Placement . Place fabric directly on top of the asphalt sealant (emulsified asphalt, tack coat) before the sealant has cooled and lost its tackiness. Lay fabric in full rolls without wrinkles and/or folds. Place the fabric per the manufacturer’s recommendations. Overlap geotextile joints to ensure full closure of the joint, but do not exceed 6 inches of overlap. Overlap transverse joints in the direction of paving. Apply 0.20 gallons per square yard of additional asphalt sealant beneath all fabric joints. Remove and replace damaged geotextiles. Removal and replacement of damaged geotextiles is subsidiary to Section 632 Pay Items.
5.Bituminous Surface Course Overlay . Place the bituminous surface course closely following the fabric laydown to avoid exposure of uncovered fabric overnight or to traffic or inclement weather. Do not allow the temperature of the hot -mix asphalt to exceed manufacturer’s recommendations. If asphalt sealant bleeds through the fabric before the placement of the overlay, apply sand or bituminous surface course evenly over the affected area to prevent fabric pick -up by construction equipment. Prevent paver or other construction equipment from turning and/or pivotin g on the fabric.
632-4.01 METHOD OF M EASUREMENT. By multiplying plan neat line width by the measured
length in final position parallel to installation centerline along the ground surface. No allowance will be made f or overlap, whet her at joints o r patc hes.
632-5.01 BASIS OF PA YMENT. Payment will be made under:
PAY ITEM Item Number Item Description Unit 632.0001.____ Paving Fabric SY 359 ALASKA 2020 SECTION 633 SILT FENCE
633-1.01 DESCRIPTION . Furnish, install, maintain, and remove temporary silt fence as shown on
the Plans or as directed.
633-2.01 MATERIALS. Use materials that conform to the following:
Geotextile Subsection 729- 2.01 Silt Fence Subsection 729- 2.04 Posts Wood 1.5- inch x 1.5- inch x 36- inch min., steel, or approved synthetic material. Prefabricated Silt Fence Meet the Plans and Section 633 requirements. Attachment Devices Staples; wire; self -locking nylon, plastic, wire ties; or other approved means to attach fabric to posts. Support Mesh between Posts 14-gage welded wire fencing, metal chain- link fabric, or geosynthetic mesh with equivalent strength. Use maximum mesh spacing of 6 inches. Use height shown on the Plans, or specified in the Bid Schedule.
633-3.01 CONSTRUCTIO N REQUIREMENTS. Install silt fence according to Plans. Use
Trenchless Detai l when installing silt fence over permanently frozen ground. Drill holes for support posts, if required. When joining to another roll, place both end posts together and wrap them with silt fence by turning them one full rotation. Drive the wrapped posts .
633-3.02 MAINTENANCE . Maintain the integrity of the fence to contain sediment in runoff until
final stabilization.
633-3.03 REMOVAL. After disturbed area has been accepted as permanently stabilized or when
sediment protection is no longer needed, remov e silt fence.
633-4.01 METHOD OF M EASUREMENT. See Section 109. Measure silt fence by the length of
fence installed. No allowance will be made for overlap, whether at joints or patches.
633-5.01 BASIS OF PA YMENT. The contract price includes installation, m aintenance, removal
and disposal of the silt fence. Payment will be made under: PAY ITEM Item Number Item Description Unit 633.0001.____ Silt Fence LF 633.0002.____ Support Mesh Reinforced Silt Fence LF
Source: Alaska Standard Specifications for Highway Construction, 2020 Edition. Pages 386–386 of 584.