Why is compaction important in asphalt paving?

Compaction is a critical process in asphalt paving primarily because it serves to reduce air voids, improve density, and enhance durability. When asphalt is laid down, it is initially loose and contains a considerable amount of air within the mixture. Compaction pushes the aggregate particles closer together, reducing the amount of air trapped in the asphalt. This reduction in air voids is essential because it helps to increase the overall density of the pavement, which directly influences its strength and longevity.

Improving density through compaction leads to a more rigid and stable pavement structure, which is less susceptible to deformation under traffic loads and environmental conditions. Additionally, well-compacted asphalt is less permeable to water, reducing the risk of moisture infiltration that can lead to premature damage and deterioration. Thus, proper compaction not only enhances the performance of the asphalt over time but also extends its service life, making it a vital step in the paving process.