Which of the following is a thin coating applied to previously paved surfaces?

The correct response identifies a tack coat as a thin layer applied to previously paved surfaces, specifically to improve the bond between the existing pavement and new material, such as asphalt. This application is essential for enhancing adhesion, which is crucial in ensuring that the layers effectively fuse together and can withstand various stresses from traffic and environmental conditions.

In pavement construction and maintenance, applying a tack coat is a critical step particularly when overlaying a surface, because it helps to reduce the chances of delamination and preserves the integrity of the pavement structure over time. The typical material used for a tack coat is an asphalt emulsion, which ensures that the new layer adheres properly to the existing surface.

Dust palliatives, fog seals, and emulsion slurry seals, while related to pavement treatments, serve different purposes. Dust palliatives are typically used to suppress dust on unpaved surfaces. Fog seals are light applications of a diluted asphalt emulsion placed on the surface to seal small cracks and provide a refreshed surface appearance. Emulsion slurry seal consists of a mixture of asphalt emulsion, aggregate, water, and additives, designed to rejuvenate and fortify the road surface rather than simply acting as a bonding layer.