[asheshouse]

Make a new folder

IL-2\MODS\New Textures\3do\airfield\Concrete2

Copy the textures from IL-2\MODS\New Textures\3do\airfield\concrete into it.
Now you can edit the texture copies in the Concrete2 folder to make new ones.

Alternatively you could create a folder in IL-2\MODS\ObjectsMap\3do\airfield\Concrete2
and copy the textures into there.
It will have the same effect, provided the mesh reference in static.ini matches it.

Ashe