What I want to do is turn my normal map into a round sidewalk texture with edge damage, indents, crevices and a little bit of stains and dirt. I'm following a tutorial I found on Youtube where the author teaches how to build a stone brick texture with the brick generator as base. I'm following that tutorial and so far I have a nice heightmap and normal, but the problem is that I need to turn that stone brick texture into a round sidewalk. The brick generator don't provide a way to make a round 1/4 of a circle base brick so I modeled a high poly mesh in Blender and baked the base normal.
The problem is that I need a way to turn it into a grayscale similar to the base image of the bricks like in the tutorial that I'm following. I saw another tutorial where the author turned a normal into a curvature map and used it as a base for his texture, but the video was deleted and I have no reference about how to do that anymore. Anyway, I guess that in this forums somebody should know how to turn a normal map into a base texture for edge damage, etc... so I came here for advise.
I'm including a pic of my normal map and also the normal map applied to my low poly mesh:

This is my normal map. As you can see is the base of a round sidewalk corner with no edge damage or wear yet. I want to use it as base for my texture but I need a way to turn it into a grayscale or something similar. I don't know how to do that so I need help.

Here is my low poly mesh with the base normal applied.
If somebody know an alternate way to make a round sidewalk texture I would like to hear it as well. Thanks for your help!