The Table of Contents for this section is available.
The work covered by this section consists of treating an existing non-asphalt base course with asphalt material in accordance with these specifications.
The treating of a non-asphalt base beneath an asphalt plant mixed pavement will not be required unless called for in the project special provisions. (See Standard Special Provisions)
Non-asphalt bases beneath an asphalt surface treatment will be treated with a prime coat.
All materials shall meet the requirements of Division 10 shown below:
Materials utilized for prime coat application shall be one of the products from the Department's "Approved Product List for Materials used for Prime Coat Applications" and shall meet the requirement shown below.
Prime Coat Materials Article 1020-3
These materials shall meet the manufacturer's specifications as submitted to and accepted by the Department. This list is on file at the Materials and Tests Unit in Raleigh.
Where the grade of prime coat material is not established by the special provisions, the Contractor may select from the approved list the grade to be used.
Prime shall be applied only when the surface to be treated is sufficiently dry and the atmospheric temperature in the shade away from artificial heat is 40F. or above for plant mix, and 50F. or above for asphalt surface treatment.
Prime coat shall not be applied on a frozen surface or when the weather is foggy or rainy.
The base shall be cleaned of objectionable dust, dirt, clay, and any other deleterious matter prior to placing the prime coat.
When directed by the Engineer, the Contractor shall dampen the surface of the base prior to the application of the prime coat.
The pressure distributor shall be designed, equipped, maintained, and operated so that asphalt material at a constant temperature may be applied uniformly on variable widths of surface at predetermined and controlled rates. Distributor equipment shall include a tachometer or synchronizer, pressure gauges, accurate volume measuring devices or a calibrated tank, and a mounted thermometer for measuring temperature.
The distributor shall be equipped with a power driven pump of sufficient capacity to distribute the required quantity of asphalt material at constant flow and uniform pressure. A full circulation spray bar adjustable laterally and vertically shall be provided and shall be adjustable in length to conform to the required width of application without overlapping. Nozzles shall be designed and maintained so as to provide equal and uniform application at all times. A hand spray hose and nozzle shall be provided to cover areas inaccessible to the spray bars. The distributor shall be equipped with a positive shut-off control for the spray bar and hand hose.
The volume of the distributor tank shall be calibrated by a commercial laboratory or the manufacturer prior to use. A calibration chart with an accurate measuring stick or a calibrated measuring stick in increments of not more than 25 gallons shall be carried on the distributor at all times for use by the Engineer.
600-6 APPLICATION RATES AND TEMPERATURES.
Prime coat shall be uniformly applied at a rate from 0.20 to 0.50 gallons per square yard. The exact rate for each application will be established by the Engineer prior to application, in accordance with the limits shown in the approved products list referenced in Article 6002.
The required rates of asphalt materials will be based on the volume of material measured at the application temperature. The temperature of the prime coat material shall be in accordance with the manufacturer's recommendations or as approved by the Engineer.
600-7 APPLICATION OF PRIME COAT.
When the plans require the base course to be constructed with side slopes flatter than 1:1 the prime shall be applied to the full width of the base including the side slopes.
Prime coat shall be applied only when the base to be treated has been approved by the Engineer.
A string line shall be placed by the Contractor to provide alignment control for the distributor during prime coat application unless waived by the Engineer.
Bridge floors, curbs, and handrails of structures and all other appurtenances shall be covered to prevent prime coat from being tracked or splattered on the structures or appurtenances.
After the prime coat has penetrated sufficiently, and when directed by the Engineer, the Contractor shall roll the primed surface until all loose base material is thoroughly bonded.
600-8 MAINTENANCE AND PROTECTION.
The prime coat shall be allowed to thoroughly penetrate the base. The Contractor shall, when so directed by the Engineer, apply blotting sand in accordance with the provisions of Section 818.
The prime shall be maintained in an acceptable condition until such time as the pavement is placed. All maintenance and replacement of damaged prime shall be done at no cost to the Department.
The quantity of prime coat to be paid for will be the number of gallons of prime coat material which has actually been placed on the road. Each distributor tank of prime coat material delivered for the project will be measured. Deductions will be made from each measured tank of material for all material placed on the road which exceeds the application rate established by the Engineer by more than 0.03 gallons per square yard.
The quantity of prime will be determined by measuring the material at the application temperature and free from air bubbles.
The quantity of prime coat, measured as provided in Article 6009, will be paid for at the contract unit price per gallon for "Prime Coat".
Blotting sand will be paid for as provided in Article 8185 for "Blotting Sand".
The above prices and payments will be full compensation for all work covered by this section including but not limited to furnishing and applying the prime, furnishing and placing granular material to protect the prime, and maintaining the prime coat.
Payment will be made under:
Prime Coat Gallon