Sounds like the water comes just from capillary action. That is very good situation compared to actual ground water pressure pushing moisture through the walls.

Sounds like the water comes just from capillary action. That is very good situation compared to actual ground water pressure pushing moisture through the walls. You should be good if you keep there good ventilation and avoid putting any wood dust or wood structures directly in contact with the concrete. Wood and concrete combined are breeding ground for dry rot and that fungal nightmare can tolerate more arid environments than any other. One trick you could try is to put some asphalt outside right next to the wall. It won't solve any underlying issues, but it can help a little bit. I think the crumbling comes from something else than moisture in your case. Probably oxidation of cement accompanied with temperature variations. You can treat that in some cases by injecting cement into the cracks in the wall. But that is very expensive.