602 CURB, COMBINATION CURB AND GUTTER, AND MONOLITHIC MEDIAN
From MDOT Policy Manual
- Construct concrete curb, concrete combination curb and gutter, concrete curb openings, concrete monolithic median, and asphalt curb.
Crusher Run Aggregate CR-6 901.01 Aggregate 901.01, Size No. 57 Curing Materials 902.07 Form Release Compound 902.08 Portland Cement Concrete 902.10, Mix No. 3 Asphalt Mix 904 Tack Coat 904.03 Reinforcement Steel 908.01 Joint Sealer 911.01 Preformed Joint Filler 911.02 Borrow Excavation 916.01
- 602.03.01 Concrete Curb, Combination Curb and Gutter, and Monolithic MedianThe portion of a divided highway separating the traveled ways for traffic in opposite directions..
- (a) Excavation. Excavate to the specified depth and to the width required to install and brace the forms. Compact the subgrade to 92 percent density per T 180, Method C, and trim to the proper shape and required grade. Remove all soft and unsuitable material and replace with approved material.
- (b) Forms.
- (1) Fixed Form Method. Ensure that all forms are properly designed and acceptable. Use full depth steel forms that are at least 10 ft in length. When installing forms where the radius of the curb face is less than 200 ft, use flexible or curved steel or wooden forms that are no more than 6 ft in length. Securely fasten and brace forms to prevent buckling, warping, or any other movement during the placing of concrete. Place the forms to a tolerance in grade and alignment of 1/4 in. in 10 ft. Thoroughly clean and coat the forms with a form release compound each time they are used.
- (2) Slip-Form Method. Refer to 603.03.01(b)(2).
- (b) Forms.
- (c) Concreting. Mix according to 915.03.04. Volumetric batching and continuous mixing will be permitted. Before placing concrete, moisten the subgrade with as much water as it can absorb. Consolidate the concrete in the forms by spading or other approved method. Remove curb face forms as soon as the concrete will retain its shape. Keep other forms in place for at least 12 hours.
- (d) Depressed Curbs. Construct depressed curbs at entrances and sidewalk ramps.
- (e) Openings. Provide an outlet for rainspouts and other drainage by constructing insert openings within the curb.
- Construct curb openings as specified.
- (f) Finishing. Strike off the concrete to the specified cross section. Finish, float, and apply a broom finish. For matching adjacent concrete surfaces, other methods of finishing may be permitted. Do not use plastering. Use a 1 in. radius edging tool on the face edge of the curb. Finish all other exposed edges with a 1/4 in. edging tool. Limit any deviation from grade and alignment of the face and top surface of curbs and medians to no more than 1/4 in. in 10 ft. Immediately after removal of the forms, repair all honeycombed and damaged areas.
- (g) Joints.
- (1) Fixed Form Method. Use 10 ft spacing between joints, except where a lesser spacing is necessary for closures and for matching expansion and contraction joints in contiguous concrete pavements. Do not use joint spacings less than 4 ft. Form the joints by using plate steel templates 1/8 to 3/16 in. thick that have a width and depth equal to the unit cross section. Do not use intermediate templates or sections of templates. Set the templates perpendicular to the line and grade of the unit. At stationary structures such as bridges and inlets, construct an expansion joint using 1/2 in. preformed expansion joint filler. Construct expansion joints at points of curves, tangents, at locations coinciding with adjoining pavement joints, and as specified or as directed. Extend the expansion joint material to the full depth of the unit cross section. Apply sealer to the entire gutter portion and 1 in. up the face of all joints. In addition, seal the entire expansion joint of monolithic medians.
- (g) Joints.
- (2) Slip-Form Method. Refer to 604.03.01(b), except use 602.03.01(g)(1) for joint spacing.
- (h) Cold Weather Construction and Curing. Refer to 520.03.02 and .12.
- (i) Backfill. After curing for at least 72 hours, use approved material to backfill the front and back of the curb, combination curb and gutter, and median to the required elevations. Complete the backfilling before rolling the adjacent roadway.
- 602.03.02 Asphalt Curb. Unless otherwise approved, use a self-propelled machine to place Asphalt curb. The machine shall form curbing that is uniform in texture, shape, and density, and to the specified template.
- Place the curb on a clean, dry, and stable base. Apply tack coat using asphalt of the type and amount as directed.
- When required, backfill the curb after it has sufficiently hardened to prevent damage. Consolidate the backfill by tamping or rolling.
602.04 MEASUREMENT AND PAYMENT.
- The payment will be full compensation for all concrete, asphalt mixes, forms, excavation, backfill, disposal of excess material, drainage openings, joint sealer, tack coat, and for all material, labor, equipment, tools, and incidentals necessary to complete the work.
- The removal and disposal of unsuitable material will be measured and paid for at the Contract unit price for Class 2 Excavation, which price includes the cost of using suitable excavation as replacement material. When Borrow or Selected Backfill is authorized as replacement material, payment will be made at the Contract unit price bid for the respective items.
- When existing curb or combination curb and gutter is removed and replaced with new curb or combination curb and gutter, the cost of the removal will be incidental to the Contract unit price for the new item.
- 602.04.01 Curb, Combination Curb and Gutter, and Monolithic MedianThe portion of a divided highway separating the traveled ways for traffic in opposite directions. will be measured and paid for at the Contract unit price per linear foot. Asphalt Curbs, Concrete Curbs, and Concrete Combination Curb and Gutter will be measured along the front face of the curb. Monolithic Concrete MedianThe portion of a divided highway separating the traveled ways for traffic in opposite directions. will be measured along the center line of the finished top of median.
- 602.04.02 Concrete Curb Opening and Curb Opening for Concrete Combination Curb and Gutter will be measured and paid for at the Contract unit price per each.