Nearly all the cement used today is portland cement, which is a hydraulic cement, or one that hardens under water. Uses of cement and concrete Nearly all skyscrapers and factories and many homes stand on concrete foundations. These buildings may also have concrete frames, walls, floors, and roofs. Concrete is used to build dams to store water and bridges to span rivers. Cars and trucks travel on concrete highways, and airplanes land on concrete runways.
Concrete tunnels run through mountains and under rivers.
Concrete pipe distributes water, carries away sewage, drains farmland, and protects underground telephone wires and electric power lines. Portland cement is used chiefly to make concrete. But it can also be mixed with soil and water to form soil-cement, which is used in road paving and dam construction and for lining reservoirs. Kinds of concrete There are special ways of strengthening concrete or of making concrete building materials. Engineers have also developed special kinds of concrete for certain uses.