304 ALASKA 2020 SECTION 609
609-1.01 DESCRIPTION. Construct curb, gutter, or combination curb and gutter. The types of
curbing are designated as follows: Type 1: Cast -in-place concrete curb Type 2: Precast concrete curb Type 3: Asphalt curb
609-2.01 MATERIALS. Use materials that conform to the following:
Concrete Section 550, Class B Bed Course Material Subsection 703- 2.03 Joint Filler Subsection 705- 2.01 Joint Sealer Subsection 705- 2.02 Joint Mortar Subsection 705- 2.04 Precast Concrete Curb Subsection 712- 2.04 Asphalt material for curbing must conform to the follo wing requirements: Asphalt Binder Subsection 702- 2.01 (Use PG 52- 28 if no Grade is specified.) Aggregate, Type II or III Subsection 703- 2.04 Mix design Requirements (ATM 417): Marshall Stability, lb., min. 1000 Percent Voids, Total Mix 2-5 Compaction, Blo ws/side 50 CONSTRUCTION REQUIREMENTS
609-3.01 GENERAL. Excavate to the required depth. Compact the base upon which curbs,
gutters, and ramps are to be set to a firm, even surface according to Subsection 203- 3.04. Make expansion joints in concrete units that comply with the dimensions and spacing shown on the Plans. Fill expansion joints with the type of preformed expansion joint filler specified. Make repairs to concrete units by removing and replacing the entire unit between scoring lines or joints. Clean all discolored concrete. The Engineer will test the finished surface with a 10- foot straightedge. Variations of more than 1/4 inch from the edge of the straightedge to the top or face of the curb or the surface of gutters and ramps, except at grade changes or curves, are unacceptable.
609-3.02 CAST -IN-PLACE CONCRETE CURBING. Use full -depth forms made of wood or metal
that are straight, free from warp, and constructed so that they will not interfere with the inspection of grade or alignment. Brace and secure forms to prevent deflection from alignment or grade during concrete placement. Coat forms with an approved form -release agent. Thoroughly moisten the foundation immediately before placing the concrete. Compact concrete in the forms by vibration or other acceptable methods. Leave forms in place until the concrete sets sufficiently so that the forms can be removed without damaging the concrete. Finish the surface according to Section 550- 3.05.Immediately upon removing the forms, rub the exposed face to a uni form surface. Do not plast er the surface. 305 ALASKA 2020 Make weakened plane contraction joints, spaced at 13 feet maximum intervals. Form each joint as a minimum 1/8 inch wide by 1/2 inch deep slot, continuous across the top and down the sides of the section. Make this slot either by sawing or scoring with a tool that will leave the corners rounded. If approved, construct the curb using a curb forming or slip- form machine. Cure the concrete according to Section 550- 3.06. During the curing period, exclude all pedestrian and vehicular traffic. Exclude vehicular traffic for additional time as directed. After the concrete sets sufficiently, refill the spaces in front and back of the curb to the required elevation with the specified material and thoroughly compact it.
609-3.03 PRECAST CONCRETE C URB. Set the curb so that the front, top line conforms to the
line and grade required. Lay curb with joints 3/8 inch to 1 inch wide. Fill the joints with joint mortar. After the mortar has set, backfill any remaining excavated areas w ith the specified material and thoroughly compact it.
609-3.04 ASPHALT CUR B. When the curb is to be constructed on a cured or aged portland
cement concrete base, asphalt pavement, or asphalt treated base, thoroughly sweep and clean the bed using compressed air. Thoroughly dry the surface and, immediately before placing the asphalt mixture, place a tack coat of asphalt material of the approved type and grade onto the surface. Construct asphalt curb using an approved, self -propelled automatic curb machine or a paver with curbing attachments that is heavy enough to compact the curb without riding above the foundation. For short sections or sections with short radii, use other approved means. Make the curb uniform in texture, shape, and density. If painting or sealing is required, curb must be clean, dry, and at ambient temperature.
609-3.05 BACKING CUR B. Construct backing curb at curb ramp locations, according to the
details and the locations shown on the Plans.
609-4.01 METHOD OF M EASUREMENT. See Section 109 and as follows:
Curb and Curb and Gutter . Measured along the front face of the curb at the finished grade elevation. No deduction in length will be made for drainage structures or ramps installed in the curb. Backing Curb. Measured along the front face of the curb. Bed Course Material . By weight or by volume measured in final position.
609-5.01 BASIS OF PA YMENT. Payment will be made under:
PAY ITEM Item Number Item Description Unit 609.0001.____ Curb, Type ___ LF 609.0002.____ Curb and Gutter, Type ___ LF 609.0003.____ Backing Curb LF 609.0004.____ Asphalt Curb LF 609.0005.____ Bed Course Material, Grading ___ TON 306 ALASKA 2020 PAY ITEM Item Number Item Description Unit 609.0006.____ Bed Course Material, Grading ___ CY 609.0007.____ Curb and Gutter, Type ___ LS 307 ALASKA 2020 SECTION 610 DITCH LINING
610-1.01 D ESCRIPTION. Construct ditch lining at the locations on the Plans or as staked.
610-2.01 MATERIALS. Use stones that are sound and durable, are no larger than 8 inches in
greatest dimension, and not more than 50 percent by weight passing a 3- inch sieve, and not more than 5% passing a 1- inch sieve, as determined by ATM 304.
610-3.01 CONSTRUCTIO N REQUIREMENTS. Excavate to the dimensions shown on the Plans.
Place and spread ditch lining materials so that the finished face is reasonably uniform and conforms with the lines and slope shown on the Plans or as directed.
610-4.01 METHOD OF M EASUREMENT. See Section 109.
610-5.01 BASIS OF PA YMENT. Excavation required below normal ditch grade is subsidiary.
Payment will be made under: PAY ITEM Item Number Item Desc ription Unit 610.0001.____ Ditch Lining CY 610.0002.____ Ditch Lining TON 610.0003.____ Ditch Lining STA 610.0004.____ Ditch Lining LS