Painting Concrete Porch

My porch has a concrete 1 / 4 "to 1 / 2" wide slot across the width at the top, about 4 feet long. Is the hydraulic cement be allowed to repair this? Then I feather the edges with a damp sponge to not show the repair? I'll be painting on it, so silicone will not work. Any help will be appreciated.

The level of the full width porch? Or the crack appears, because a party has fallen?

If this is the case, you may want to consider talking to a service concrete repair, aka "mudjack have repaired the porch. They pump a cement slurry under the porch, bringing it to its original level.

If the crack is along the boundary between the porch and the foundation of home and the porch itself is in decent shape, I'd be looking to cement mortar to fill the void, or bring mudjack the back porch until IPO.

If the crack crosses the porch itself, and the porch is level on the crack, then I would consider closing the gap with an epoxy resin. The epoxy is stronger than the cement / mortar.

Place a ruler on the crack and see if the porch slopes / inclines to one side of the crack, etc. ... This will also give you an idea as to whether it will be possible to "mix" of compensation in the highest level, it is in the crack, the easier it is to blend the repair.

Fun

take a grinder and open up the crack, then fill with a mixture of Portland cement. This way you can keep the high level with porch and not have to worry about softening ...