The purpose is to waterproof cement cracks to prevent more water intrusion.
Small concrete surfaces can’t be fixed with concrete.
Small cracks become big cracks.
Cracks look ugly and unkempt.
Water damage will get worse.
Textured caulk, concrete sealer or pourable concrete grout are options for repairing small cracks. Use a concrete repair mix like an epoxy or latex compounds for cracks of ¼ inch. Mortar mixes work best for large cracks over ½ inch, and chipped edges.
I used Sika, polyurethane, self-leveling, flexible caulk because it’s quick to apply, expands, and can add 2nd coat next year.
Prepare the cracked area for patching. Use a hammer and chisel on cracked or crumbling cement, and to open cracks. Scrub with a wire brush and screwdriver to dislodge any loose bits. Sweep or use a shop vac.
Apply the material with caulk gun with smallest hole necessary to reduce mess. Use paper napkins to clean gun tip and caulking line. Force it down into the crack with a tool or your finger so it hits both sides and seals the bottom to make it waterproof. Then smooth it level to the surrounding concrete. Different mixes cure differently; consult the directions.
Mortar mixes are 1/4 Portland cement, 3/4 masonry sand, and only enough water to form a thick paste. Moisten the area and eliminate air pockets by pressing down firmly on the mortar. Smooth the patch to the proper level.
Or fill big cracks partially with damp sand or foam leaving 1/2 inch to the surface of the crack to be filled with grout. Overfill due to drying and shrinkage.
Mixing vinyl concrete patch has only 20 minute window. Start by wetting the crack before spreading and forcing the material into the crack with a tool or finger. Fill the crack in layers no thicker than 1/4 inch to account for shrinkage. Damp sand can raise the depth of the crack to 1/2 inch.