Why is it important to have a good drainage system under asphalt pavements?

A well-designed drainage system beneath asphalt pavements is crucial primarily because it significantly reduces the risk of moisture infiltration and damage to the pavement structure. Water accumulation can lead to several issues, such as the weakening of the sub-base and the development of cracks in the asphalt itself. If water is allowed to enter and remain in the pavement layers, it can freeze and expand, further exacerbating these cracks and potentially leading to potholes or other forms of structural failure.

Moreover, effective drainage helps maintain the integrity of the underlying soil, ensuring that it does not become overly saturated, which can compromise the support for the pavement. By directing water away from the pavement surface and minimizing its impact on the structural components, a good drainage system enhances the longevity and durability of the asphalt pavement. This preventative measure not only helps preserve the pavement’s functionality but also mitigates the long-term costs associated with repairs and maintenance.

Other choices pertain to aesthetic appeal, maintenance reduction, and safety, which, while important in their own right, do not capture the primary role of drainage in preventing moisture-related damage.