PLAIN CONCRETE

Major ingredients of concrete are following as:

  I.            Binding material (such as cement, lime, polymer)

  II.           Fine aggregate (e.g. sand)

  III.          Coarse aggregates (e.g.: crushed stone, jelly)

  IV.          Water.

A small quantity of admixtures such as water proofing agents, air entraining agents, workability agents etc. can also be added to impart special properties to the plain concrete mixture.

Strength of concrete varies Depending upon the proportion of ingredient. For a particular strength it is possible to determine the proportion of the ingredients by mix design procedure. the ingredients are proportioned as 1:1:2, 1:1 1 :3, 1:2:4, 1:3:6 and 1:4:8, the ratio of weights of cement to sand to coarse aggregate In the absence of mix design.

In proportioning of concrete it should be remember that voids in coarse gregates are filled with sand and in sand, the voids are filled with cement paste. Proportion of ingredients generally adopted for many works are shown in given table.

            Proportion of cement, sand and coarse aggregates in concrete