SECTION 407: TACK COAT
407.1 Description
This Work consists of providi ng and applying asphalt Material t o an existing HMA, WMA, or portland cement concrete pavement surface.
407.2 Materials
The Contractor shall use one (1) of the following asphalt Mater ials types for the tack coat: 1. CSS-1, CSS-1H, or SS-1, or SS-1H emulsified asphalt; 2. Performance-graded asphalt binder; or 3. Project Manager approved selection from the Department’s Approved Products List . The Contractor shall provide the asphalt Materials in accordanc e with Section 402, “Asphalt Materials and Mineral Admixtures.”
407.3 Construction Requirements
The Project Manager will determine the tack coat application ra te and as indicated in
407.3.1 Temperature and Weather Limitations
The Contractor shall: 1. Not apply tack coat on a wet surface. 2. Not apply emulsified asphalt wh en the air temperature is bel ow the manufacturers recommended application temperature.
407.3.2 Equipment
The Equipment shall include an as phalt distributor and Equipmen t for heating asphalt Material. The Contractor shall provide Equipment that is in ac cordance with Section 408, “Prime Coat.”
407.3.3 Preparation of Surface
The surfaces and edges to be tack coated shall be dry, patched, cleaned, and free of dirt, surface moisture, vegetation and other Deleterious Materials or irregularities.
407.3.4 Application of Asphalt Material
The Contractor shall: 1. Uniformly apply asphalt Material with a pressure distributor at a rate determined by the Project Manager (to provide a “residual” asphalt cement con tent of from 0.04 gal per square yard to 0.08 gal per square yard); 2. Ensure that the nozzles on the pressure distributor are full y open and at the same angle from the spray bar, approximately 30°; 3. Keep the spray bar at a height above the pavement surface to provide for a double or triple lap of the applied asphalt Material; 4. Keep traffic off of the tack coat, unless otherwise approved by the Project Manager. If the Roadway being paved is closed to traffic, the Contractor may place tack coat a Section 407: Tack Coat Page 174 maximum of 24 h ahead of the laydown operation. If the Roadway being paved is open to traffic, place the tack coat only over the area that ca n be paved during that Day’s laydown operation. If the Contractor uses an emulsified asphalt tack coat, the Contractor may begin paving operat ions after the emulsified asp halt is cured. 5. Reapplication of tack coat damaged by traffic or constructio n Equipment will be at no cost to the Department.
407.4 Method of Measurement
The Department will consider any water added to further dilute emulsified asphalts Incidental to Asphalt Material for Tack Coat and no separate payment will be made.
407.5 BASIS OF PAYMENT Pay Item Pay Unit
Asphalt Material for Tack Coat T o n
407.5.1 Work Included in Payment
The Department will consider as included in the payment for th e pay item(s) listed in this section and will not measure or pay separately for the followin g Work: 1. Providing, mixing, heating, and applying asphalt Materials t o the roadbed with an asphalt distributor; 2. Shipping/Delivery to Project site; 3. Sampling and Testing; and 4. Water. Section 408: Prime Coat Page 175