Which factor primarily influences the longevity of an asphalt pavement?

The longevity of asphalt pavement is largely influenced by the quality of the asphalt binder. The asphalt binder acts as the glue that holds the aggregate together and provides flexibility and durability to the pavement. A high-quality binder can help to withstand various stresses, such as temperature fluctuations, traffic loads, and environmental conditions. It contributes significantly to the pavement's resistance to cracking, rutting, and overall wear over time.

Using a high-performance binder can enhance the pavement's performance characteristics, which is essential for its longevity. On the other hand, a lower quality binder may lead to premature failures, reducing the lifespan of the pavement. While factors like the type of aggregate, installation conditions, and asphalt layer thickness are important, they do not have the same direct impact on the longevity of the pavement as the binder quality does. Thus, the quality of the asphalt binder is a crucial aspect in determining how well the pavement performs over its intended lifespan.