Removal and replacement is used for more severe deterioration, especially when the underlying base has been affected. The damaged areas are squared off, saw cut, and excavated to the appropriate depth depending on the subsurface conditions. New rock base is then added, if required, and compacted in preparation for the new asphalt surface. Finally, hot-mixed asphalt is placed over this layer in multiple lifts and compacted. As with resurfacing, the entire surface should be treated with a sealcoat to protect and enhance the appearance of the asphalt.