Is there any way to repair cracked concrete?

Yes. A crack can be filled, injected, or routed and sealed, and the right method turns on how wide it is and whether the concrete is still moving. Epoxy injected into a crack holds to the concrete better than the concrete itself holds together under tension, so it can make the slab structurally sound again even where the crack is only 0.002 inch wide. Rusting steel behind the crack, or a slab that will go on moving, are the cases where epoxy may be the wrong choice.

For a crack expected to move a little, TxDOT's concrete repair manual routs a V-shaped groove about 3/8 inch deep along it and seals it to keep water out.