What is mix-Design?

Concrete is an extremely versatile building material, it can be designed for strength ranging from M10 to M100 & workability ranging from 0 mm slump to pumpable concrete with 150 mm slump. In all these cases the basic ingredient of concrete are the same, but it is their relative proportioning that makes it difference. Basic ingredients of concrete: 1. cement: it is the basic binding material in concrete 2. Water: it hydrates cement & also makes concrete workable. 3. Coarse aggregates: it is the basic building component of concrete. 4. Fine Aggregates: along with cement paste it forms mortar grout & fills the voids in coarse aggregates. 5. Admixtures: They enhance certain properties of concrete e.g. gain of strength, workability, setting time, imperviousness etc.

Concrete mix design is the method of correct proportioning of ingredients of concrete, in order to optimize the properties of concrete as per site requirements.

In other words, we determine the relative proportions of ingredients of concrete to achieve desired strength & workability in a most economical way.

Advantages of Mix-Design?

Mix design aims to achieve good quality concrete at site economically.

1. Quality control means: • Better Strength • Better Imperviousness & Durability • Dense & homogeneous concrete

2. Economy: • Economy in Cement Consumption: It is possible to save up to 15% of cement for M20 grade of concrete with concrete mix-design. In fact higher the grade of concrete more are the savings. Lower cement content also results in lower heat of hydration & hence reduces shrinkage cracks.

• Best use of Available material: Site conditions often restrict the quality & quantity of ingredient materials. Concrete mix design offers a lot of flexibility on type of aggregates to be used in mix-design. Mix design can give an economical solution based on the available materials if they meet the basic IS requirements. This can lead to saving transportation costs from longer distances.

• Other Properties: Mix design can help us to achieve form finishes, high early strengths for early Deshuttering, concrete with better flexural strengths, concrete with pumpability & concrete with lower densities.