Concrete can be said to have been used for thousands of years, if the words is taken generally to mean a hard building material produced from a mixture of cement, sand, gravel and stone. The Assyrians and Babylonians used clay to bind sand and stones, and the ancient Egyptians discovered lime and gypsum. The Romans mixed slaked time with volcanic ash and constructed aqueducts, Bridges and buildings, some of which survive.
Lime remained a popular cementing material until the discovery of the process of making Portland cement shortly after 1800. The name was given to it by Joseph Aspdin, and Englishman, because he thought its products resembled the limestone quarried at Portland in Dorset, England. It is a man made cement which, since 1900, has been almost the only cement used in the building industry.
Concrete mixtures for small jobs and repairs at home are easily made, but the design and erection of important concrete structures calls for a combination of artistic and scientific skills. Scientists have developed reinforced concrete strengthened with steel, prepossessed concrete and concrete shells which may be simple and functional or more complex to give building added beauty.