What is a common component in the design of pavements?

Subgrade preparation is a fundamental aspect of pavement design that directly affects the integrity and longevity of the pavement structure. The subgrade serves as the foundation of the pavement system and provides support to the layers above it. Proper preparation involves evaluating and improving the soil conditions to ensure that it has the appropriate strength, stability, and drainage characteristics required to support anticipated loads.

This preparation may include processes such as removing weak soils, compaction, moisture control, and stabilization. An adequately prepared subgrade minimizes potential issues like settling, cracking, and deformation in the pavement surface, ultimately enhancing the performance and durability of the pavement. Effective subgrade preparation is vital for the overall engineering and design of roadways, parking lots, and other paved surfaces, making it a common and critical component in pavement design.

The other options, while they may have their applications in specific contexts, do not play as pivotal a role in the overarching design principles of pavement. Insulation layers and air circulation systems are typically not components of standard pavement structures, while decoration patterns might contribute to aesthetic elements but do not impact the structural integrity of the pavement itself.