The goal is to have 100% surface contact. A replacement is required for any damage greater than 2 inches. ensure that you lay the grinder’s disc flat against the high spots you’re planning to grind down.
in the case of huge grinds, a scarifier with an associated vacuum is used to remove the first layer of concrete. can you grind concrete down? This method is also suitable for smoothening ridges, removing sealed surfaces, and leveling out. If the high section is not too big and the concrete not very thick, i think it's less work to bang it out with a sledgehammer and redo it with concrete then to grind it.
