Can I fill driveway cracks with polymeric sand? Can hardened polymeric sand be reused?

I have a concrete driveway. It have developed cracks of 1/8 inch to 3/4 inch in width. I am constantly removing weeds which grow in the cracks. I bought of polymeric sand to fill the cracks on the assumption that this can be a reasonable  fix for the appearance and weed problem. However, before I had a chance the used the sand the bags got wet and hardened. My question is, can hardened polymeric sand be broken up and reused? And, is polymeric sand a reasonable fix for a cracked driveway?
P.S. Using tar caulk of those fiberous slats that you stick in the cracks can be pretty expensive.

Daryl,

This is probably not what you wanted to hear, but if your polymeric sand has really gotten wet, it is probably a lost cause.  I have used polymeric sand in the past to set paving stones and they essentially get glued together.  I would think that they would work for filling a crack in the cement, but this would only apply to the dry sand which easily flowes into the cracks and crevices and then gardens and adheres when wet.

Hate to be the bearer of bad news, but best of luck.

Eric