Concrete is a mixture of Cement, Sand, and Coarse Aggregate mixed in water in a specified ratio. Depending upon the cement content, concrete is decided whether it is rich concrete or lean concrete. Concrete having a ratio of 1:2:4 and above is known as rich concrete. Rich concrete is used in structural elements where strength is the prime objective. Whereas concrete has a ratio of 1:3:6 and below, which is known as lean concrete.