Oh it burns, I spent a few weeks while with GE working with Johnson Controls at the Kennedy Space center. We invented an ablative coating for the launch pads for the Atlas rockets and the Shuttles. Every launch they would burn up the concrete pads but the coating we came up with provided them with 5 launches before they needed repair. It burns, it just takes abot 25,000F for 30 seconds to do it!

im sorry for my blunder on the burning part! 25,000 degrees!!!!!!!!!!! WOW! thats MUY CALIENTE! i will rephrase my comment.......CONCRETE WILL NEVER BURN UNLESS BENEATH SATURN V BOOSTER ROCKET ! man thats hot!

Concrete can crack but doesn't have to. For something the size of a countertop, I'd say he's fine so long as some allowance is made during installation for shrinkage as it cures over the long-term (i.e. there aren't rigid anchors holding it in place with no ability to "give" for movement/contraction). In other words (as with most things) the details will make or break the installation (literally). Slotted holes, joints, expandable sealants and the like are your friends. A simple anchor on the bottom into a slotted track would probably be fine for this kind of install.

There are some very good salt-resistant concretes available now too. Concrete piles are being used in dams, bridge footings & piles, piers, etc. with very low failure rates now. If the wrong mix is chosen, yes it will fail quickly but there are very good application-specific mixes available these days. . .

Charles - your from Cave Creek? Had Chili Beer once...only once... wasn't man enough to finish it! Talk about CALIENTE!

The Romans made things out of concrete, then the knowledge of it was lost for centuries. The Coliseum in rome has large poured concrete structures in it.

lubemaster...............chili-beer is brewed right here in cave creek az. the water comes from an abandoned gold mine. local health dept checks water on regular basis for clarity. the brewery makes about 6 different beers per year. the one they sell the most world wide...............chili-beer! now that will melt concrete! owner keeps plane at airport i work at. on his tail is bottle of chili-beer. his name ed chilleen, great guy good beers/good food. great p-car stop for munchies and a cold one.