The composite material was invented by French gardener Joseph Monier in 1849 and patented in 1867.
However, other materials are often used to reinforce concrete e.g. organic and inorganic fibres, composites in different forms.
The other purpose of providing reinforcement in concrete is to hold the tension cracked sections together.
The reinforcement in a RC structure, such as a steel bar, has to undergo the same strain or deformation as the surrounding concrete in order to prevent discontinuity, slip or separation of the two materials under load.
This load transfer is achieved by means of bond (anchorage) and is idealized as a continuous stress field that develops in the vicinity of the steel-concrete interface.