Most specifications for partial-depth patches require the patch perimeter to be saw cut to a certain depth. I believe that this is good practice because it prevents featheredging of the patch material; however, I'm uncomfortable with the polished edge that is left after sawing. I believe the polished edge inhibits bonding of the repair material. Should this edge be prepared further?
If abrasive blasting is also specified to remove rust from reinforcing steel or to remove loose concrete particles, then the edges of the sawcut can also be lightly blasted to provide a more roughened surface. If abrasive blasting is not part of patch preparation, consider making the sawcuts with a dry diamond blade rather than with a blade that requires water for cooling. Dry sawcutting does not leave a polished surface.