Foremost, it is a grave misconception that the repair of cracks in a concrete floor during the concrete polishing process is truly repairing the concrete slab. Unfortunately due to the weight and nature of concrete itself, concrete can recrack even post repairs. The epoxy mortars used to ‘repair’ the crack are merely topically recreating a flush, smooth surface but will not ‘glue’ the concrete back together vertically within.
A bright side however, unless there are underlying issues below the concrete slab which allow future movement, most of the settling occurs in the first year of the concrete curing. This curing and movement causes cracks to visual appear through the top of the concrete. A old, settled concrete floor can than be correctly repaired and many times, that crack no longer continues because the movement has subsided.
The final patches come out flush, smooth and visually appealing compared to that of the rigid, prior trip hazards that also harbored dirt and debris during cleaning operations. It should not be misconstrued that your cracks will be invisible post concrete polishing or ‘made to match’ the concrete itself. While effort can be made to use fine sands or tints, the patches will more than likely be apparent and fully visible. If the visual character of smooth but apparent cracks in a concrete floor is unacceptable to a facility floor, the only option is to hide them with an epoxy floor coating installation.