What is the primary purpose of compaction in asphalt paving?

The primary purpose of compaction in asphalt paving is fundamentally tied to increasing density, reducing air voids, and improving stability. When asphalt is laid down, it contains air spaces that can affect its longevity and performance. Compaction reduces these air voids, leading to a denser and more uniformly distributed material.

A denser asphalt surface is essential for a durable pavement that can withstand traffic loads and environmental factors without deforming or deteriorating prematurely. Additionally, reducing air voids enhances the resistance of the asphalt to moisture infiltration and oxidative damage, which are critical factors in pavement performance.

Moreover, adequate compaction ensures that the asphalt achieves the desired strength and load-bearing capacity, ultimately contributing to a longer lifespan for the pavement. This contrasts with the other choices where reducing material cost, speeding up the process, or altering the color do not address the fundamental properties and long-term performance benefits that proper compaction provides.