The tack spray bar height must allow what during application?

• A. Even moisture only
• B. Double coverage or overspray
• C. No overspray
• D. Full adhesion

Answer: (B)

The key idea is that tack coat needs to wet the surface evenly to create a bonding layer for the next asphalt lift. The spray bar height should be set so the coating is enough to cover all areas, including edges and texture, without causing heavy pooling. Allowing double coverage or a little overspray ensures every surface detail gets a tack film, reducing the risk of dry spots where the new layer wouldn’t adhere. If you’re too close, you’ll get thick streaks or runs; too far, and you’ll miss spots. A light overspray to achieve complete wetting across the surface is the practical balance, so the correct understanding is that the bar height should allow double coverage or overspray.