Design a concrete mix step by step: target mean strength, water–cement ratio, water and cement content, fly ash / GGBS, admixture, fine and coarse aggregate per m³, field correction for moisture, quantities per 50 kg bag and trial mixes. Durability limits from IS 456 Table 5. Download the full calculation sheet as a PDF.
| Step | IS 10262:2019 | IS 10262:2009 | IS 10262:1982 | ACI 211.1-91 |
|---|---|---|---|---|
| Target strength | Higher of fck+1.65S and fck+X | fck+1.65S | fck+tS (t = 1.65), S by site control | fck+1.65S |
| w/c ratio | Fig. 1 curves by cement strength, capped by IS 456 | Experience / IS 456 Table 5 limit | Fig. 1 or Fig. 2 curves A–F | Table by average strength |
| Water | Table 4 (50 mm slump) +3% per 25 mm, aggregate shape, admixture | Table 2, same adjustments | Table d.1/d.2 with corrections for CF, sand zone, w/c, rounded aggregate | Table 3 by slump band |
| Aggregate split | Coarse aggregate volume by zone (Table 5) | Same (Table 3) | Sand % of total aggregate | Dry-rodded volume by fineness modulus |
| Entrapped air | 1.5 / 1.0 / 0.8% | Not deducted | 3 / 2 / 1% | Table 3 |
Trial mixes needed A calculated mix is only the starting point. Every code requires trial batches to check workability and cube strength, and adjustment of the proportions before use. Read more: target mean strength (IS 10262) · concrete grades and mix ratios · materials for M20 concrete.