IS 10262:2019 Concrete Mix Design Method
IS 10262:2019 proportions concrete through a fixed sequence of steps, from the target strength requirement through to the final aggregate quantities and trial verification. This page walks through that sequence. Open the calculator pre-loaded with the standard’s M40 example.
The calculation sequence
- Calculate the target mean strength, f′ck = fck + 1.65s, where s is the standard deviation.
- Select the water-cement ratio, taking the lower of the strength-based value and the IS 456 durability-based maximum.
- Select the free water content from the nominal aggregate size and required slump, adjusted for aggregate shape and admixture.
- Calculate cementitious content as water ÷ adopted w/c, checked against the IS 456 minimum cement content.
- Find the coarse aggregate proportion from IS 10262:2019 Table 5, adjusted for w/c ratio and pumping.
- Using the absolute volume method, compute the volumes of cement, water and admixture, subtract them from 1 m³ to get the total aggregate volume, then split it into coarse and fine aggregate.
- Apply aggregate moisture correction to convert the SSD quantities into site batch quantities.
- Confirm the design through trial mixes.
Worked example
For M40, the standard’s own worked example gives a target mean strength of 48.25 N/mm², water content of 140 kg/m³, cement content of 350 kg/m³, fine aggregate of 896 kg/m³, coarse aggregate of 1140 kg/m³ and about 7 kg/m³ of admixture. These figures are reproduced by the calculator’s M40 example.
Questions this page answers
What is the difference between characteristic and target strength?
Characteristic strength is the specified 28-day strength, with 5% of test results permitted to fall below it. Target mean strength adds a margin of 1.65s to that value for use in the mix design.
Do I still need trials?
Yes, always. The calculated proportions are a preliminary estimate and must be confirmed by trial batches before use.