Quick question about artillery

[JAFFA]

Does anyone know if it's possible to bombard a village or town hex and create a rubble hex IF no enermy units are occupying it.

Situation:
I have a town on a main highway which is covered by several of my artillery units, I know that my opponent will be racing up and down this road with tanks and supplies, but I cannot get any of my unit to block it due to his lines.

If I bombard the town with my big guns will it eventually turn to rubble.
If not, why not.

Also while i'm on it, why can engineers clear rubble in towns, BUT not create it, I.e Blow the crap out of stuff, example warsaw.

Jaf