We put in a travertine floor about a year ago. Now, there are small
bubbles
or voids that are breaking, and leaving a hole in the floor.
Is there a product or something that I can fill these with so they will be
flush with the floor.

Grout that they use for floor tile..Thats how the floor installer did in our
new house. Also in our walk-in shower-tumbled travertine tile floor and
walls.
Comes in nearly every color so you can probably match your travertine as
close as you'd like.

R