Fill in all cracks on the surface with concrete repair caulk. Cut the tip of the tube at a 45-degree angle and insert it into a caulking gun for easy application. Smooth the caulk with a putty knife.
Mark any expansion joints with duct tape. Lay a strip of tape over each joint so that they will not be filled while you're resurfacing. The joints allow the concrete to expand and contract.
Set straight-edge boards (two-by-fours or one-by-sixes--whatever is handy) down to frame both sides of the walkway. Drive stakes into the ground alongside the boards to secure them in an upright position. These framing boards will help keep the resurfacing concrete level and prevent you from losing any of it.
Mix the resurfacing concrete. Pour pour 2 1/2 quarts of water and a 20-lb. bag of concrete resurfacer into a large bucket. Mix with a drill and mixing paddle for two minutes.
Pour the mix onto the walkway surface and spread it with a flat steel trowel. Add texture by gently sweeping a push broom over the wet surface. Remove the duct tape from the joints and allow the surface to set for 24 hours.
Fill a paint tray with a clear waterborne masonry sealer. Apply the sealer to the walkway surface with a paint roller. Let the sealer dry for 24 hours before using the walkway. The sealer will protect the concrete from the elements and help prevent damage.