For the pool interior, we used an American Olean Tile.

The Granite Pavers shown are 1.5" thick and are dry-set with tight joints on a prepared base of gravel and stone dust. If they were set in concrete, over time water would get in the cracks and pop the pavers up. You might be able to use tile set in concrete if you seal the surface every two years to keep the water out. Talk to American Olean or another pool tile company.