Not in all cases. Concrete removal and replacement is the traditional method for sidewalk repair when the damage is so extensive that alternative methods are not enough to make the necessary repairs. Today there are a wide variety of sidewalk repair technologies available that, when implemented correctly, can result in major savings of both time and money.
In some instances if the sidewalk concrete is in good condition and there is only a vertical misalignment along the seam between slabs (See Stub Toe and Longitudinal Slope in Sidewalk Inspection Criteria) it may be possible to correct the problem by one of the following methods.
Concrete raising is a repair method that lifts concrete sidewalk slabs back to their original position by pressure injecting cement or non cement material under the sidewalk. Holes are drilled through the slab and grout is injected to raise the concrete slab or to fill the voids under them. Although it is less costly than replacement, it is only effective on sunken sidewalks. There are many contractors that specialize in performing this type of work.
This is a good alternative when the sidewalk concrete is in satisfactory condition with no cracks or structural defects. One draw back to this method is the greater the slab needs to be adjusted the greater the possibility of the slab settling in the future.
Concrete grinding is a relatively new technology used to remove trip hazards in concrete walkways by reducing slight protrusions on a concrete surface by removing a thin layer of concrete. After grinding, the surface is left even on both sides with a gradual slope instead of a dangerous edge.
Concrete grinding is a good alternative if the lip (stub toe) between concrete slabs is between 1/2" to 1".
If your sidewalk slab is cracked, pitted or there are gaps between slabs that have been identified as the only problem with the sidewalk and the remaining concrete is in good condition it may be possible to correct the problem without replacing the concrete by simply filling the cracks, pits, or gaps. See the following for information related to this repair method.