Comment by eindiran

The thing that makes them "caustic or acidic" is that they are acidic (~3pH), by virtue of having dissolved carbon dioxide (ie carbonic acid) + acidic preservatives in them. You are putting them into your stomach (with your gastric acid, ~2pH). If you spilled your stomach contents on the concrete shipping dock repeatedly, it would weaken the concrete much faster. Now, I don't drink soda and they are objectively bad for your teeth, but the fact that they eat away at concrete does not seem like the right reason to avoid them.