IS method of mix design with steps-

The concrete mix design is done by IS 10262-2009 using following steps-

1. Calculation of target mean strength –The concrete mix design is done for specific target strength which is calculated first. It is calculated by using formula, f’_ck = f_ck + t.S; where,

f’_ck = target mean strength after 28 days

f_ck = characteristics compressive strength at 28 days

S = standard deviation from IS 456

T = tolerance factor from IS 456

1. Selection of water-cement ratio- The w/c ratio is selected from the graph of generalized relationship between w/c ratio and compressive strength. The selected w/c ratio is checked against the limiting w/c ratio and lower of two is adopted.

2. Selection of water content- The maximum water content per cubic meter of concrete with nominal maximum size of aggregate s finalized in this step. The water content adopted is used for computing cement content in next step.

3. Calculation of cementitous material content – From adopted w/c ratio and selected maximum water content the quantity of cementious materials is calculated. It is checked against the minimum cementitous content for durability requirement ad larger of the two values is adopted as cement content.

4. Calculation of coarse aggregate proportion –The volume of coarse aggregate per unit volume of total aggregate is chosen in this step based on nominal maximum size of aggregate

5. Selection of combination of coarse aggregate fractions- The different sizes viz. 10 mm , 20 mm , 25 mm are taken in proportion from grading , confirming in table 2 of IS 383

6. Calculation of fine aggregate proportion- From above steps, absolute volume of all ingredients of concrete the mix proportion is calculated for said mix design of concrete.