Hello mate.

I actually have a full blown tutorial using DMM on cmivfx.com about just that using DMM.
I have inside exactly what you are looking for.

http://www.youtube.com/watch?v=oLBn5c_xlnA

Here is a quick tut for you.

Create a poly cube, give it a few divisions but not to many, perhaps 3 or 4 as the higher you go the longer the sim. Make it pretty thin for the road, duplicate it and place this under the road so our road can rest on this second slab and not fall away.

Now go into DMM and open the shelf and menu.

Select both objects and click the make DMM object from mesh.
Now both object will be DMM objects.
If you press play they will fall with gravity.

Select the bottom slab below the road and select the last icon on the shelf called “show DMM asset manager”
Click the passive button on the top, this will allow it to become a passive object and not move with force, your road will now settle on the slab and not fall.

Now assign a material to it, in the DMM menu choose material and assign preset, choose something like weak crystal, now your road has a material which means it mimics weak crystal which is a pretty cool set for what you are looking for.

We can then add a splinter cage to give your fractured objects shape to it, so it does not just look like fractured triangles.  import a cage from your maya library. You can find the cages as .obj objects in your DMM library which is situated on your local C:\Program Files (x86)\Pixelux\DMM Plugin for Maya\Setup\DMM Libraries\splinters\meshes This is the default place for you .obj cages.

Import one and place it over your entire road, make sure that it covers your whole object or clipping will occure and we dont want that.

Then select your cage and then your road and hit the icon that sais apply cage to selected object and we done creating the road:)

Now create a DMM primitive, I would select the sphere. then once again turn it into a passive object form you manager discussed above, this will allow you to animate the sphere , animate the sphere just under the road and make it collide a tad, remember DMM objects can only be effected by other DMM objects.
Once you have this then you can play it back and boom, your road should shatter accordingly. You can go into the manager once your road or desired DMM object is selected and change the res, giving you more pieces or less etc.

Another thing to note is that you can apply maya forces to your road so it will fall faster etc.
Create a filed with nothing selected, then select you road then the filed and in your menu hit the apply maya forces to selected and bam, you have the force attached now and you can change its settings:)

I hope this helps mate and good luck.

This is a basic tut but should get you well on your way, the rest is up to you with changing attributes to suite what you are looking for.

PS: Just graze the road with the sphere for a crack look and in the material node which is the second last icon on the shelf, turn your toughness pretty high which will allow for cracks and shatters instead of blowing the road to pieces:)

All the best.