Difference Between Tack Coat and Prime Coat

Key Difference

Tack coat and prime coat are both used in road construction but serve different purposes. A tack coat is applied to the surface of an existing pavement to promote adhesion with a new overlay of asphalt. In contrast, a prime coat is applied to a newly constructed, unpaved base course to protect the substrate from weather and to provide a bond for the asphalt that will be laid on it.

Comparative Analysis

1. Purpose:
   • Tack Coat: Enhances adhesion between old and new pavement layers.
   • Prime Coat: Protects base course and aids in bonding with new asphalt.
2. Application Surface:
   • Tack Coat: Applied on existing pavement.
   • Prime Coat: Applied on a new, unpaved base.

Table Summary of Tack Coat vs Prime Coat

Aspect	Tack Coat	Prime Coat
Purpose	Enhances adhesion between old and new pavement layers.	Protects base course and aids in bonding with new asphalt.
Application Surface	Applied on existing pavement.	Applied on a new, unpaved base.

Tack coat and prime coat are essential in pavement construction for ensuring layer cohesion and protecting base courses, respectively