What is tack coat?

Tack coat (also known as bond coat) is a light application of asphalt emulsion between hot mix asphalt layers designed to create a strong adhesive bond without slippage. Heavier applications may be used under porous layers or around patches where it also functions as a seal coat.

Why use tack coat?

Without a tack coat, the asphalt layers in a roadway may separate, which reduces the structural integrity of the pavement and may allow water to penetrate the structure.

What type of emulsion should be used for tack coats?

The type of emulsion used for tack coats varies from country to country. Normal practice in the USA is to use a slow-setting emulsion that is diluted with water before application. Cationic rapid-setting or specially designed, less tracking emulsions that are applied undiluted are becoming more popular. See your state’s Product Locations & Applications page for more options.

Why use prime coat?

Prime coats protect the integrity of the granular base during construction and help reduce dust. In the case of a base which is to be covered with a thin hot mix layer or a chip seal for a low volume roadway, priming ensures a good bond between the seal and the underlying surface which otherwise would have a tendency to delaminate.

Why use asphalt emulsion prime?

Compared to cutback asphalt primes, emulsion primes are more environmentally friendly. Solventless prime coats are available in some areas. Check your state’s Product Locations & Applications page for availability.

What type of emulsion is most suitable for emulsion prime?

Slow-setting grades of asphalt emulsions (diluted with water before application) are suitable. To ensure good penetration on dense granular or stabilized bases, the surface may need to be scarified and dampened before application of the emulsion. See your state’s Product Locations & Applications page for more options.