Proportioning

The principle object of proportioning concrete is to achieve requisite strength with desired workability for which due attention should be paid to the selection of cement and aggregates according to the specification. Some of the considerations to be taken note of are:

1. The mix must be workable so that it can be placed and finished without extra effort. 

2. Low cement consumption consistent with the attainment of desired properties. 3. High cement content improves strength, impermeability, density and workability. 

4. With cement content, ingredients and workability remaining constant, the strength and impermeability of concrete increase with the density of mix.