The factory was constructed out of concrete.

The foundation is bedded in concrete.

Concrete can be reinforced by putting steel bars inside it.

The building will be made of concrete on a steel framework.

If the demolition of buildings is uncontrolled, a fine city is in danger of becoming nothing more than a concrete jungle.

Fires are less frightening today than they once were, because more and more houses are built of concrete, and concrete houses do not burn as easily as the old wooden ones.