What does a pavement need to avoid when spreading loads to the subgrade?

A pavement must avoid over-taxing the strength of the subgrade when spreading loads because this can lead to significant structural issues. The subgrade serves as the foundational layer that supports the entire pavement system. If the loads applied to the pavement exceed the subgrade's bearing capacity, it can result in deformation, permanent settlement, or even failure of the pavement structure. Proper engineering design ensures that the pavement distributes loads adequately, preventing localized stress concentrations that could compromise the integrity of the subgrade.

In contrast, uneven distribution, insufficient thickness, and excessive surface texture may also present issues in pavement design, but they affect performance in different ways. Uneven distribution can lead to localized failures, while insufficient thickness might not provide the necessary structural support. Excessive surface texture could impact vehicle traction or ride quality but does not directly tie to the subgrade's ability to handle loads.