ABSTRACT
Concrete is by far the most widely used construction material in the world. Its wide use is due both to its versatility as well as its durability [1]. There are structures that were built in Roman times using materials similar to modern concrete that are still standing today. Two major events in the development of concrete occurred in the eighteenth century: the invention of Portland cement and the use of steel bars to reinforce concrete. In the twentieth century, most of the research in using concrete focused on getting the most utility out of every pound of concrete.
