4.3. Item 302 Bituminous Tack Coat

Tack Coat is an application of liquid asphalt on an existing pavement. Tack coat, as the name implies is   intended only to provide a “tacky” surface between the  surfaces.

Tack Coat consists of a light application of asphalt material to an existing road surface before placing a Hot Mix Asphalt (HMA) course.

Material Requirements

Bituminous material shall either be Rapid Curing (RC) Cut-back or Emulsified Asphalt, whichever is called for in the Bill of Quantities.

Range of Temperature:

Temperature Range = 10oC (min.) to 71 oC (max.)

Required Minimum Testing Requirements:

Tests: 1 – Q, Quality Test for every 40 tons or 200 drums

Equipment Requirements

  • Self-powered pressure asphalt distributor including the following accessories:
  • Tachometer
  • Pressure gauges
  • Calibrated tank
  • Power broom or other mechanical sweeping equipment
  • Water Sprinkler
  • Armored Thermometer

Construction Procedure

  1. Prior to the application of the bituminous tack coat, The Project Engineer should designate the beginning and ending points of the area to be covered.
  2. The surface shall be slightly sprayed/sprinkled with water but not saturated.
  3. The rate of application shall be within the range of 0.20 to 0.70 liters per square meters. The atmospheric temperature shall be above 15.56oC.
  4. After application of tack coat, the surface should be allowed to cure without being disturbed.
  5. Ensure that the traffic should not be allowed on the tack coat.