Correct option is C
In road construction and maintenance, different types of bituminous coatings are applied to ensure proper adhesion between layers and to protect the pavement. The specific type of coating used depends on the purpose and the existing conditions of the pavement.
Definitions of Coating Types:
Prime Coat:
Applied to a granular base before laying the bituminous layer.
Its purpose is to bind the loose particles of the base and to provide a better bond with the bituminous layer.
Seal Coat:
Applied to the top surface of the bituminous pavement.
Its purpose is to seal the surface and prevent water infiltration, as well as to provide a wearing surface.
Tack Coat:
Applied on an existing bituminous or concrete surface before laying a new bituminous layer.
Its purpose is to ensure proper bonding between the existing surface and the new bituminous layer, especially when the existing pavement is impervious.
Wear Coat:
This term is less commonly used and typically refers to the top layer of pavement that directly bears traffic. It is not specifically a coating applied like the others listed.
Application of Tack Coat:
Tack coat is crucial when a new bituminous surfacing is applied over an existing impervious surface, such as an old bituminous pavement or a concrete road. It ensures that the new layer adheres properly to the old surface, preventing issues like delamination.
