Municipal pothole repair and utility cut patching is a high-visibility job. If you leave a bump in the road, every car that hits it will curse your crew. The final step of any good asphalt patch is the compaction, and doing it right with a water-equipped plate compactor is an art form.
When the hot mix asphalt (HMA) is shoveled into the cut, it sits slightly "proud" (higher) than the surrounding existing roadway. This is the "roll-down" allowance. Before I bring the plate compactor over, I make sure the water tank is flowing and the base plate is slick. The critical technique here is called "pinching the edge." I do not run the compactor straight down the middle of the fresh patch. Instead, I start on the perimeter. I position the machine so that 80% of the base plate is riding on the old, cold, existing asphalt, and only 20% is overlapping the fresh, hot patch.
By running the perimeter first, I forcefully drive the new asphalt laterally into the saw-cut face of the old asphalt, creating a tight, waterproof seam. If you start in the middle, the asphalt will simply mush and spread outward, leaving a weak, porous gap at the edges where water will infiltrate, freeze, and blow the patch out next winter. Once the edges are pinched tight, I slowly work my way toward the center of the patch, using overlapping passes until the fresh asphalt is perfectly flush with the existing grade. It’s all about controlling the material, not just beating it flat.
