Patching

Asphalt patching consists of saw cutting the existing asphalt around the failed area, ensuring that all cuts are straight and corners squared. The failed area is excavated to the specified depth, which is at least as deep as or deeper than the existing asphalt, and the failed material is hauled off-site for recycling. Alternatively, for larger failed areas, a milling machine may be brought in for a more efficient method of removing large quantities of asphalt.

The existing aggregate base is inspected for proper load-bearing strength and repaired as required or as specified. Typical base repair consists of removal of failed base aggregates and replacing with fresh stone and compacted using vibratory compaction techniques.

The sidewalls of the cut area are tacked using an asphalt tack coat (typically CRS-1 or CRS-2) to ensure proper bonding of the new hot mix asphalt to the existing asphalt.

The appropriate hot mix asphalt types are applied (either by hand or via paver) at the specified depths. We typically use only superpave hot mix asphalt which consists of the latest hot mix asphalt designs that resulted from the Strategic Highway Research Program. The most commonly used superpave mixes in North Carolina are SF9.5A, S9.5B, S9.5C, I-19, and B-25. The asphalt types of I-2 and H-Binder are legacy asphalt mixes and thus are used less often.

Extreme care is taken to ensure that all cuts are straight with no over-cuts, corners are squared, base is properly inspected and repaired, and asphalt is properly laid and leveled (raked) to ensure a consistently high-quality patch every time. Vibratory rollers are used to ensure proper compaction.