Re-tread or Double Dressing
This process is very similar to the hot tar &chip process,but instead of applying the bituminous emulsion to an existing blacktop or concrete surface, the binder is then sprayed on, or incorporated, to the unbound aggregate surface.Typical unbound surface suitable for re-tread/double dressing.
Re-Tread
Re-tread involves incorporating the first coat of binder into the aggregate with harrows the two more coats of binder are sprayed on, each followed by dressing of hard, clean chippings, forming a thick layer of bound material sealing the aggregate beneath and provides a smooth running surface ideal for long driveways and road.
Double Dressing 
Double dressing is the same principal are re-tread with the deduction of an initial first coat of binder and harrowing taking place. Providing the same appearance but not as thick.