When is full-depth patching generally recommended over partial-depth patching?

Full-depth patching is generally recommended over partial-depth patching when the damage extends through the entire asphalt layer and into the underlying base or subgrade. This indicates a structural failure in the pavement that requires a more extensive repair. Full-depth patching involves removing all of the damaged pavement layers down to a solid, stable foundation and replacing them with new materials. This provides a structurally sound patch that can withstand traffic loads and prevent further deterioration. Partial-depth patching, on the other hand, only involves removing and replacing the damaged surface layers. It is typically used for repairing surface distresses that do not extend into the underlying layers, such as shallow potholes or raveling. If the damage extends into the base or subgrade, partial-depth patching will not provide a durable repair and the distress will likely reappear quickly. Therefore, full-depth patching is necessary to address structural failures and provide a long-lasting repair.