At Simons Golf we have Capillary Concrete (specially designed concrete for bunkers) in our bunkers. Therefore, players should be aware that this can cause some inconvenience that allows for relief.

The concrete floor is an immovable obstruction and if there is a real risk of hitting it in the swing, there is relief under Rule 16.1c.
https://www.randa.org/da-DK/rog/the-rules-of-golf/rule-16

This means that you can drop a ball in the bunker without penalty within a club’s length of the nearest place where there is no risk, and not closer to the hole. If you cannot find a place in the bunker not nearer the hole (or if you just do not want to drop in the bunker), you may drop behind the bunker on the back-on-the-line with one penalty stroke. If you are in doubt about how close the concrete is to the ball, you must investigate this by carefully sticking a tee into the sand.

Section 16.1c of the Rules of Golf entitles a player to relief for a ball in a bunker if an abnormal course condition interferes with the stroke. The concrete base will be if there is not enough sand under the ball. It will be the player’s assessment as to whether the intended shot has such a depth that it will hit the concrete floor.

Interpretation 8.1a/7 and Interpretation 12.2b/2 give the player the right to check with a tee as to whether an obstruction could interfere with the player’s stroke, and this also applies in a bunker.

If you can feel the concrete, you can also take relief according to the above procedure.