We're talking about mortar here, not concrete. I.e. the "paste" that's put between bricks and other stone work to "glue" it together.

But of course normal bricks are also subject to spalling, but it's very rare that they'll Gail catastrophically, mostly you'll get a crack or two.

Europe's full of old brick houses that cone chimneys that were made before using specialized materials for them was mandated.

You can safely build such structures, they just require building and usage techniques that go along with them, e.g. using a double layer of brick, or gradually heating up the chimney to get the humidity out of the bricks and mortar.