There are four main methods at your disposal which you can use to fix cracks in concrete.
Repairing large cracks in concrete patio.
This helps the repair material to key into the crack creating a mechanical bond in addition to the chemical bond between the patch material and the concrete.
Installations of concrete can last hundreds of years but sooner or later most end up developing small cracks gaps holes and crevices.
Concrete cracks cannot be patched with concrete since concrete contains aggregate rock pieces that are too large to fit in cracks.
If your concrete path patio or driveway has begun to.
Instead for cracks up to 1 2 inch wide and 1 4 inch deep you should use a polymer based sanded acrylic latex filler that you inject into the crack with a caulking gun and smooth over with a putty knife.
Now you can move onto the actual methods of fixing a crack in the concrete.
The secret to fixing wide concrete cracks is to undercut the sides of the crack to give it an inverted v shape.