Readymix concrete is manufactured under controlled operations and transported and placed at site using sophistied equipment and methods. In 2011, there were 72,924 workers working in 2,223 companies that produced Ready Mix Concrete in the United States.
There are different grades of concrete like M15, M20, M25, M60, etc. For smallscale constructions; normal grade concretes like M10, M15 M20 are used. For large scale constructions; standardgrade highgrade concrete like M25,M40, M45, M50, etc are used. There is a requirement of design mix in highgrade concretes.