What is the normal application rate of tack for close graded mixes?

The normal application rate of tack for close graded mixes is typically between 0.02 and 0.08 gallons per square yard. This application rate is optimal for ensuring that the tack coat properly adheres the layers of asphalt together, which is crucial for the longevity and structural integrity of the pavement. Applying tack at this rate allows for sufficient bonding without over-saturating the surface, which can lead to issues such as tracking or bleeding of asphalt.

In close graded mixes, where the aggregate sizes are more uniform, proper bonding is essential to ensure that the overlaid material adheres effectively and does not lead to delamination or other pavement failures. The chosen range strikes a balance between achieving good adhesion and avoiding excess material that may not contribute to the performance of the pavement structure.

Understanding the nuances of tack application is critical in asphalt paving to achieve the best results for durability and performance. The other options reflect application rates that either fall short of or exceed the typical requirements for close graded mixes, potentially leading to suboptimal bonding or unnecessary material use.