What type of asphalt mix is designed to have larger air voids for drainage?

The type of asphalt mix designed to have larger air voids for drainage is open-graded asphalt. This specific mix includes larger aggregate sizes and a higher proportion of air voids compared to other types of asphalt, allowing for better drainage of water. The design is intentional, creating pathways for water to flow through the pavement, which helps reduce issues like hydroplaning and minimizes water accumulation on the surface during rainstorms.

In contrast, dense-graded asphalt is formulated to offer a smoother surface and is compacted tightly to minimize air voids, which effectively inhibits drainage. Wearing surface asphalt primarily aims for durability and skid resistance rather than drainage performance, while stabilized asphalt mixes are designed to enhance strength and stability through the addition of additives or aggregates rather than focusing on drainage characteristics. Thus, open-graded asphalt is specifically suited for applications where drainage is a critical concern.