You have a major problem. concrete is not water proof (liquid or vapor)or really even water resistent. If you look at a concrete pool or tank, a thin plaster coating provides the water proof layer - not the concrete. Your best bet is to remove the concrete, lay down a real water proof layer and reinstall the concrete. You can put so called water proof paints/materials on the cement, but they will only last a few years. In the mean time, you will have completely rotted the wood framing that supports the concrete slab.
reinforced concrete and stone
concrete
Concrete.
The Colosseum is built with concrete, faced stone, stone and marble.
They used concrete.
Concrete
Yes, concrete can absorb water.
Concrete
concrete or bricks
No,,l
topsoil supports structures built on top of it