There are a few reasons for barbel degeneration in Corydoras. Rough substrate whatever the medium is one, bacterial issues is another (and likely the more common, depending), water conditions (ammonia, nitrite, nitrate), more rarely barbel nipping by another species.
I believe I have seen Imagitarium sand mentioned on CorydorasWorld with no serious negatives, so far as the "sand" is concerned. The bacterial issue would bother me however.
@RainGamma how many cories do you have in this tank? What other fish do you have?
What are the parameters, meaning the GH (hardness) and pH and temperature? What are the results of testys for ammonia, nitrite or nitrate?
While the cory may "live" without its barbels, this is still a very serious issue as the underlying cause can lead to much worse problems.