What is the purpose of preparing the subgrade before surfacing materials are placed?

Preparing the subgrade is a crucial step in the construction process because it establishes the foundation for any subsequent surfacing materials. The process of fine grading involves leveling and smoothing the soil to create a uniform surface that meets specific design criteria. By achieving a fine grade, the subgrade can effectively support the weight of the surfacing materials and ensure proper drainage and water management.

Additionally, a well-prepared subgrade minimizes the risk of future problems such as settling, cracking, or erosion that can occur if the underlying material is uneven or improperly compacted. This preparation also allows for the correct drainage patterns to be established, which is essential for mitigating water accumulation and potential damage to both the surface and the underlying soil structure.

While other options may relate to different aspects of grading or stormwater management, they do not specifically emphasize the importance of preparing the subgrade precisely for surfacing materials. Hence, fine grading is key to ensuring durability and effectiveness in the overall construction project.