What is the function of air voids in an asphalt mixture?

The function of air voids in an asphalt mixture is primarily related to influencing durability. Air voids are intentional spaces within the asphalt that help to accommodate the expansion and contraction of the material under temperature changes. By allowing for this movement, air voids can prevent cracking and other forms of distress, thereby enhancing the durability of the pavement. Properly managed air void content also contributes to the resistance of the asphalt mix to moisture damage and fatigue over time, which is crucial for maintaining longevity in roadway performance.

In terms of other aspects such as load-bearing capacity, flexibility, and temperature control, air voids do play a role, but their most significant contribution is in the context of durability and how well the asphalt mixture can withstand the stresses and environmental factors it faces over its lifespan.