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605-1 DESCRIPTION.

The work covered by this section consists of treating an existing asphalt or concrete surface with asphalt material in accordance with these specifications.

Tack coat shall be applied beneath each layer of asphalt plant mix base or pavement to be placed except where a prime coat or a newly placed asphalt surface treatment mat coat has been applied, unless otherwise directed by the Engineer.

605-2 MATERIALS.

All materials shall meet the requirements of Division 10 shown below:

Asphalt cement, Grade AC-20 Article 1020-2 (See Standard Special Provisions)

Asphalt, Grade RS-1H Article 1020-6

Asphalt, Grade CRS-1H Article 1020-7

Asphalt, Grade CRS-1 Article 1020-7

Asphalt, Grade HFMS-1 Article 1020-6

Asphalt, Grade CRS-2 Article 1020-7

The tack coat material shall not be diluted or mixed with water, solvents, or other materials prior to application.

Unless otherwise specified in the project special provisions, the Contractor may utilize any of the grades of tack coat material specified in this article.

When tack coat is required beneath an open-graded asphalt friction course, the asphalt grade to be used on the project and rate of application will be specified in the job mix formula.

605-3 WEATHER LIMITATIONS.

Tack coat shall be applied only when the surface to be treated is sufficiently dry and when the atmospheric temperature is 35F. or above in the shade away from artificial heat.

Tack coat shall not be applied when the weather is foggy or rainy.

605-4 SURFACE PREPARATION.

The existing asphalt or concrete surface to which tack coat is to be applied shall be cleaned of all dust and foreign material prior to placing the tack coat.

The Contractor shall remove grass, dirt, and other materials from the edge of the existing pavement prior to the placement of tack coat.

605-5 ACCEPTANCE OF ASPHALT MATERIALS.

The acceptance of asphalt materials shall be in accordance with the provisions of Article 1020­1.

605-6 APPLICATION EQUIPMENT.

The Contractor shall provide equipment for heating and applying the asphalt material in accordance with the requirements of Article 600­5.

605-7 APPLICATION RATES AND TEMPERATURES.

Tack coat shall be uniformly applied at a rate from 0.02 to 0.05 gallons per square yard. The exact rate for each application will be established by the Engineer. A different rate of application for different layers or surfaces may be established by the Engineer.

The required rates of application will be based on the volume of material at the application temperature. The temperature of the tack coat material at the time of application shall be within the ranges shown in Table 605­1.

605-8 APPLICATION OF TACK COAT.

No more tack coat material shall be applied than can be covered with base, binder, or surface course material during the next day's operation except where public traffic is being maintained.

Where public traffic is being maintained, no more tack coat shall be applied than can be covered during the same day's operation. 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. In the event that tack coat material is not covered in the same day's operation, the Engineer may require the application of suitable granular material or other means to provide a safe traffic condition at no additional cost to the Department.

The tack coat material shall be applied with a distributor spray bar which can be adjusted to uniformly coat the entire surface at the directed rate unless otherwise approved by the Engineer. A hand hose attachment shall only be used on irregular areas and areas inaccessible to the spray bar. Application of tack coat material by the use of a hand hose attachment to the irregular and inaccessible areas shall be uniform and complete.

Tack coat shall be applied only in the presence of and as directed by the Engineer. No base or surface mixture shall be deposited thereon until the tack coat has sufficiently cured.

Contact surfaces of headers, curbs, gutters, manholes, vertical faces of old pavements, and all exposed transverse and longitudinal edges of each course shall be painted or sprayed with tack coat before mixture is placed adjacent to such surfaces.

Bridge floors, curbs, and handrails of structures, and all other appurtenances shall be covered to prevent tack coat from being tracked or splattered on the structures or appurtenances.

605-9 PROTECTION OF TACK COAT.

After the tack coat has been applied it shall be protected until it has cured for a sufficient length of time to prevent it from being picked up by traffic.

605-10 COMPENSATION.

There will be no direct payment for the work covered by this section.

Payment at the contract unit prices for the various items covered by Sections 630, 635, 640, 645, 650, and 654 will be full compensation for all work covered by this section.