The groove over the crack may be made with hand held tools concrete saw or pneumatic tools which is then cleaned by air blasting sandblasting or water jetting to remove grease oil or dirt.
How to chase a concrete wall.
Amazon tool shop here.
After cleaning with water the surface must be dried before the application of the sealant.
Vertical chases should not be any deeper than one third of the total wall thickness.
In a cavity wall vertical chases should be no deeper than one third of the thickness of the skin they are being placed in.
No chases horizontal or vertical should be made back to back.
The simple rules for cutting chases in walls.
This is phil from armeg showing my learners how to use an armeg tri cutter to chase a wall to fit and electrical flush socket box.