6-4 Table 605-2
APPLICATION TEMPERATURE FOR TACK COAT Asphalt Material Temperature Range Asphalt Binder, Grade PG 58-28 or PG 64-22 350 - 400°F Emulsified Asphalt, Grade RS -1H 130 - 160°F Emulsified Asphalt, Grade CRS -1 130 - 160°F Emulsified Asphalt, Grade CRS -1H 130 - 160°F Emulsified Asphalt, Grade HFMS -1 130 - 160°F Emulsified Asphalt, Grade CRS -2 130 - 160°F
605-8 Application of Tack Coat
Apply only as much tack coat material as can be covered with base, intermediate or surface course material during the next day's operation except where public traffic is being maintained. If public traffic is being maintained, cover the tack coat in the same day's operation . Provide safe traffic conditions. If need ed, apply suitable granular material so it bonds to the tack coat. In addition, the Engineer may limit the application of tack coat in advance of the paving operation depending on traffic conditions, project location, proximity to business or residential areas or other reasons. Take necessary precautions to limit the tracking or accumulation of tack coat on either existing or newly constructed pavements. Excessive accumulation of tack coat require s corrective measures. Apply tack coat with a distributor spray bar that can be adjusted to uniformly coat the entire surface at the rate directed by the Engineer . Use a hand hose attachment only on irregular areas and areas inaccessible to the spray bar. Cover these a reas unifor mly and completely. Apply tack coat as directed by and in the presence of the Engineer. Do not place any asphalt mixture until the tack coat has sufficiently cured. Apply tack coat to all exposed transverse and longitudinal edges of each course before mixture is placed adjacent to such surfaces. Apply tack coat to contact surfaces of headers, curbs, gutters, manholes and vertical faces of old pavements. Cover bridge floors, curbs and handrails of structures and all other appurtenances to protect them from tracking or splattering tack coat material.
605-9 Protection of Tack Coat
After the tack coat has been applied, protect it until it has cured for a sufficient length of time to prevent it from being picked up by traffic.
605-10 Measurement and Payment
There will be no direct payment for the work covered by this section. Payment at the contract unit prices for the various mix items covered by Sections 610, 650 and 654 will be full compensation for all work covered by this section.
607-1 Description
Perform the work covered by this section including, but not limited to , milling and re -milling the pavement at locations, depths, widths and typical sections indicated in the contract ; cleaning the milled surface; loading, hauling and stockpiling the milled material for use in recycled asphalt mixtures ; and disposal of any excess milled material.
6-5 Except where the milled material is used in the work or where otherwise direct ed by the
Engineer , provide areas outside the right of way to dispose of milled material, which sha ll be property of the Contractor.
607-2 Equipment
Use a self -propelled unit c apable of removing the existing asphalt pavement to the depths, widths and typical sections shown in the contract. Use milling machines designed and built exclusively for pavement milling operations and with sufficient power, traction and stability to accurately maintain depth of cut and slope. Use milling machines equipped with an electronic control system that will automatically control the longitudinal profile and cross slope of the milled pavement surface . Accomplish this through the use of a mobile grade reference, an erected string line, joint matching shoe, slope control systems or a combination of approved methods. Use an erected fixed stringline when required by the contract . Otherwise, use a mobile grade reference s ystem capable of averaging the existing grade or pavement profile over at least 30 f eet. Use either a non-contacting laser or sonar type ski systems with at least 3 referencing stations mounted on the milling machine at a length of at least 24 feet. Coor dinate the position of the grade control system such that the grade sensor is at the approximate midpoint of the mobile reference system. Use a machine capable of leaving a uniform surface suitable for handling traffic without damage to the underlying pavement structure. Use a milling machine and other loading equipment capable of loading milled material to be used in other parts of the work without segregation. Provide additional equipment necessary to satisfactorily remove the pavement in the area of manholes, water valves, curb , gutter and other obstructions. Equip the milling equipment with a means of effectively limiting the amount of dust escaping from the removal operation in accordance with Federal , State and local air pollution control laws and regulations.
607-3 Construction Methods
Mill the existing pavement to restore the pavement surface to a uniform longitudinal profile and cross section in accordance with typical sections shown in the plans. Where indicated in the contract, remove pavement to a specified depth and produce a specified cross slope. Mill intersections and other irregular areas unless otherwise directed by the Engineer . The Contractor may elect to make multiple cuts to achieve the required depth of cut or cross slope required by the plans. Establish the longitudinal profile of the milled surface by a mobile string line on the side of the cut nearest the centerline of the road. Establish the cross slo pe of the milled surface by an automatic cross slope control mechanism or by a second skid sensing device located on the opposite edge of the cut. The Engineer may waive the requirement for automatic grade and cross slope controls where conditions warrant . Operate the milling equipment so as to prevent damage to the underlying pavement structure, utilities, drainage facilities, curb and gutter, paved surfaces outside the milled area and any other appurtenances. Produce milled pavement surfaces that are reasonably smooth and free of excessive scarification marks, gouges, ridges, continuous grooves or other damage. Repair any leveling or patching required as a result of negligence by the Contractor with hot asphalt plant mix in a manner acceptable to the En gineer. Coordinate the adjustment of manholes, meter boxes and valve boxes with the milling operation in accordance with Article 858 -3 including a temporary asphalt ramp. Variable depth milling is intended to improve the cross - sectional slope of the pavement.
6-6 When necessary, the contractor may remove the top section of a utility and use a bridge steel
plate placed to cover the entire width of the structure, ensuring no debris is dropped inside the structure. Backfill with compacted material and hot m ix asphalt as a temporary riding surface as well as any further necessary requirements of the utility owner. This steel plate must be capable of carrying any traffic load carried by the facility. Where necessary, double- reference the location of each str ucture that has been removed and maintain a map of their location. Construct a temporary ramp of asphalt plant mix to extend a minimum of 3 f eet around raised structures before opening to traffic . The Engineer may require re -milling of any area exhibiting pavement laminations , scabbing or other defects. “Scabbing” is defined as a thin layer of existing pavement that remains after milling and has the potential to delaminate. Thoroughly clean the milled pavement surface of all loose aggregate particles, du st and other objectionable material. Disposing or wasting of oversize pieces of pavement or loose aggregate material will not be permitted within the right of way. Conduct pavement removal operations so as to effectively minimize the amount of dust being emitted. Plan and conduct the operation so it is safe for persons and property adjacent to the work including the traveling public.
607-4 Tolerance
Remove the existing pavement to the depth required by the contract. The Engineer may vary the depth of milling by not more than one inch. In the event the directed depth of milling cut is altered by the Engineer more than one inch, either the Department or the Contractor may reques t an adjustment in unit price in accordance with Article 104- 3. In administering Article 22 104-3, the Department will give no consideration to value given to RAP due to the deletion or reduction in quantity of milling. Article 104- 3 will not apply to the item of Incidental Milling .
607-5 Measurement and Payment
A.Milled Asphalt Pavement Milled Asphalt Pavement , __" Depth will be measured and paid as the actual number of square yards of pavement surface milled in accordance with this specification . In measuring this quantity, the length will be the actual length milled, measured along the pavement surface. The width will be the width required by the plans or directed by the Engineer , measured along the pavement surface. Areas to be paid under th is item include mainline travel lanes , full width turn lanes greater than 500 feet in length , collector lanes, shoulders, and any additional equipment necessa ry to remove pavement in the area of manholes, water valves, curb, gutter and other obstructions.
B.Variable Depth Milled Asphalt Pavement Milling Asphalt Pavement , __" to __" will be measured and paid as the actual number of square yards of pavement surfa ce milled in accordance with this s pecification . In measuring this quantity, the length will be the actual length milled, measured along the pavement surface. The width will be the width required by the plans or directed by the Engineer , measured along the pavement surface. Areas to be paid under this item include mainline travel lanes , full width turn lanes greater than 500 feet in length, collector lanes, shoulders , and any additional equipment necessary to remove pavement in the area of manholes, water valves, curb, gutter and other obstructions . For each square yard that the Engineer directs to be milled, including, but not limited to, the mainline, turn lanes, bus loading and unloading areas, widening for bus or truck U-turns , shoulde rs, intersections and crossovers requiring any additional equipment necessary to remove pavement in the area of manholes, water valves, curb, gutter and other obstructions, compensation will be made at the contract unit price per square yard for Milling As phalt Pavement, __" Depth or Milling Asphalt Pavemen t, __" to __".
Source: North Carolina Standard Specifications for Roads and Structures, 2024 Edition. Pages 260–262 of 857.