On the front stoop, fourth stair up (right side), a chunk of the concrete has long since broken off & disappeared. You can "kind of" see it in the picture. The integrity of the remaining concrete is good, so I suspect something knocked that corner off many years ago.
My plan is to drill several small vertical holes in the step, insert short steel rods, form up the outside edge, and pour a "replacement corner" on it.
I realize this is not the ideal solution - so please don't tell me to rip the entire porch of the house and start over (we know who's most likely to recommend that...).
My question is, what mortar/concrete mix should I use, to give the best adhesion and the most probable likelihood of success?