Open or gap graded mixtures tend to drain down more readily than densely graded mixtures.

• A. Not Applicable
• B. Cannot Determine
• C. False
• D. True

Answer: (D)

The main idea is that how easily the binder can move through the voids in the aggregate determines drain-down. Open or gap-graded mixes have larger, more interconnected air voids, so there’s a continuous path for the asphalt binder to flow downward under gravity when the material is hot or sits in place. That means the binder can drain out of the aggregate structure, especially if the asphalt content is high or the mix is stored or laid while it’s still warm. In contrast, densely graded mixes have smaller, less connected voids, which trap the binder within the aggregate and resist drainage. So the statement is true: open or gap-graded mixtures tend to drain down more readily than densely graded mixtures.