Why selective removal is used
Existing concrete may need to be opened for new utilities, altered layouts, damaged-area replacement or revised foundations. The goal is usually controlled access to a defined area, not unnecessary removal of sound adjacent work.
Know what may be below the slab
Utilities and reinforcing can be concealed. Available drawings, scanning information and field verification should be coordinated before cutting. The exact investigation method depends on the project and the responsibility of the project team.
Removal affects the space around it
Dust, debris movement, equipment access and temporary closures matter in active facilities. Phasing and protection requirements should be discussed before demolition starts so the work can fit the site's operating conditions.
Replacement is part of the plan
A good scope defines not only what is removed but what replaces it: base conditions, reinforcing, concrete limits, finish, joints and tie-ins to surrounding surfaces. That helps the repaired area function as part of the existing facility rather than as an isolated patch.