Q:

Can I have a very dense asteroid belt ring around a star?

I'd like to have an advanced civilization that lives in a ring around their sun, but a ring planet just can't work.  In this case, they are among densely agglomerated asteroids (with life support, there's no atmosphere or anything) about as far out as our first asteroid belt, and have built bridges, etc. between the asteroids, many of which have been hollowed out for habitats.
Could there be a 'thick,' densely packed ring of asteroids that form a belt around the sun, or how long could that last.  Could they be orbiting in a manner that keeps them from clumping together at least for a while?  I'm imagining the distance to be like something out of Star Wars, whereby they have managed to stabilize and bridge those rocks.
EDIT: (Additional, maybe superfluous information), as requested.  
The intent is to have a continuous civilization (could be far-future human) in a ring around a star.  A ring-planet that is not the inevitably impossible ring-planet.   The geography is flexible, but to keep it scientifically possible (it might not be), I'll venture a ring of large rocks the majority of which range between 10-20km of size, and several times that distance between each other.
The very basic question (hence the science-based tag), is if this is remotely possible.  It sounds like it won't be, at least around a star.
EDIT2: I wonder, if I reduce the size of the rocks to mere meters (e.g. - 20m diameter) orbiting, if it allows for bouncing off each other, but remaining dispersed such as this, for at least human scales of time, say 30,000 years.  If this introduces a new question, please let me know, and I'll remove this edit and add a new question.

A:

This won't work.
The reason that asteroid belts can persist is that they don't have enough mass to accrete into a planet. If an asteroid belt had the density depicted in typical science fiction (meters or kilometers apart) there would be far more than enough mass to collapse into a planet. Which they would promptly (on an astronomical scale) do. 
In our asteroid belt the distance between asteroids is, on average, about 2 million miles and its entire mass is about 4% that of our moon.
The solution is to have these aliens inhabiting a ring system of a planet. Saturn's rings, for instance, are made up of rocks that are on the order of meters apart.

