Concrete

Concr e t e is a manufactured product or mixture, wich is used as a construction material. It has many advantages, like: hardness, it molds to any shape you want, strong in compression. A disadvantage is the weakness in tension force, but this is not always true... there is a kind of concrete which is resistant and strong in the two forces, and it is reinforced concrete. It is fire-water-resistant and it has been used since ancient times.