Concrete is a mixture of cement, sand, stone aggregates and water. A cage of steel rods used together with the concrete mix leads to the formation of Reinforced Cement Concrete popularly known as RCC.
Concrete has two main stages
1) Fresh Concrete
2) Hardened Concrete
Fresh Concrete should be stable and should not segregate or bleed during transportation and placing when it is subjected to forces during handling operations of limited nature. The mix should be cohesive and mobile enough to be placed in the form around the reinforcement and should be able to cast into the required shape without loosing continuity or homogeneity under the available techniques of placing the concrete at a particular job. The mix should be amenable to proper and through compaction into a dense, compact concrete with minimum voids under the existing facilities of compaction at the site. A best mix from the point of view of campactibility should achieve a 99 percent elimination of the original voids present.