The "huge" is the problem here. In order to store any useful amount of energy, you'd need way too much. We use water because it's readily available, cheap, easy

The "huge" is the problem here. In order to store any useful amount of energy, you'd need way too much. We use water because it's readily available, cheap, easy to transport, and relatively easy to store. Concrete is already harder to transport (you need to correctly grasp, stack and release the blocks).