What does the term "Air Voids" refer to in asphalt mixture design?

The term "Air Voids" in asphalt mixture design specifically refers to the spaces between aggregate particles within the asphalt matrix. These voids are critical in determining the performance and durability of the asphalt pavement. Air voids play a significant role in the overall mixture's stability, density, and permeability, influencing how well the asphalt can support loads and resist environmental conditions.

In a well-designed asphalt mixture, a specific range of air void content is maintained to ensure that there is enough room for the binder to coat the aggregate particles while also allowing for compaction and preventing issues such as moisture infiltration. Proper management of air voids contributes directly to the longevity of the pavement and its ability to withstand dynamic loads and temperature fluctuations.

Understanding air voids helps asphalt professionals design mixtures that achieve the desired mechanical properties and service life, making this knowledge essential for effective asphalt pavement construction.