Concrete Mix Design

Methodology — Concrete Mix Design

Scope

Proportions the constituents of concrete (cement, mineral admixture, water, chemical admixture, fiber, and coarse and fine aggregate) for ordinary and standard grades (M10–M60) by the absolute volume method, per IS 10262:2019 Annex A (OPC/PPC, no mineral admixture), Annex B (with fly ash) and Annex C (with GGBS). These three annexes share one procedure — only the mineral-admixture step differs — which is why this page covers all three with a single calculator. Silica fume and micro silica use the same mineral-admixture step as fly ash/GGBS (only the specific gravity differs).

Not yet built: high strength concrete M65 and above (Annex D), self-compacting concrete (Annex E), and mass concrete (Annex F) use different proportioning methods and are a separate future addition.

Page layout

The Mix Design tab is split 60:40. The left column (60%) is the working procedure, A-1 through A-12, each section scrolling independently of the right column. The right column (40%) is reference material only — the IS 456/10262/383 tables the calculator itself uses — so you can check a figure without leaving the page.

Procedure (mirrors the annex clause numbers)

1. A-1 Stipulations: every input IS 10262 Annex A-1 requires before proportioning — grade, type of concrete, cement type, MSA, exposure, minimum/maximum cement content, maximum free w/c, workability, method of placing, degree of site control, aggregate shape/type, and the chemical/mineral admixture in use (picked once, at the top of the Mix Design tab, and echoed here).
2. A-2 Test data: specific gravity, water absorption and field moisture for every constituent (coarse aggregate SG/water absorption by the wire basket method, fine aggregate by the pycnometer method, IS 2386 Part 3), plus sieve-analysis-based blending of coarse aggregate, fine aggregate and all-in aggregate, read automatically from whatever gradations are saved in the Coarse Aggregate Gradation for Concrete and Fine Aggregate Gradation for Concrete modules for this project — nothing needs to be re-entered.
3. A-3 Target strength: f'ck = max(fck + 1.65×S, fck + X), using the assumed standard deviation S (Table 2) and factor X (Table 1) for the selected grade.
4. A-4 Air content: entrapped air per Table 3, by nominal maximum aggregate size (MSA).
5. A-5 Water-cement(itious) ratio: read from Fig. 1 (reference panel) for the target strength and cement strength class, then checked against the durability limit for the exposure condition (IS 456 Table 5) — the lower of the two is adopted, entered once in A-1.
6. A-6 Water content: from Table 4 (per MSA, for 50 mm slump, angular aggregate) — per Cl. 5.3, first reduced by 10 kg for sub-angular aggregate, 15 kg for gravel with some crushed particles, or 20 kg for rounded gravel (0 for angular/manufactured aggregate); then adjusted +3% per 25 mm above 50 mm slump; then reduced for the water-reducing admixture dosage used. The raw (unrounded) result is always shown; enter your own adopted/rounded figure in "Adopted / rounded values" — you may go lower than the calculated estimate. Example: 20 mm MSA, sub-angular aggregate, 75 mm slump → 186 − 10 = 176 kg, × 1.03 (25 mm over 50 mm) = 181.28 kg, then reduced for admixture.
7. A-7 Cementitious content: adopted water ÷ adopted ratio (raw figure shown; adopt your own rounded value the same way as A-6), checked against the exposure's minimum cement content; for Annex B/C, optionally increased and then split into cement + mineral admixture by the chosen percentage.
8. A-8 Coarse/fine aggregate proportion: from Table 5 (by MSA and sand zone, at w/c = 0.50), corrected ±0.01 for every ±0.05 the adopted ratio differs from 0.50, and reduced up to 10% further for pumpable mixes (Cl. 5.5.2). "Method of placing" in A-1 doubles as the pumpable/non-pumpable switch. Table 5 is calibrated for angular crushed aggregate only — a note is shown recommending a trial-batch check for other aggregate shapes.
9. A-9 Mix calculation: absolute volume method — volumes of cement, mineral admixture, water, chemical admixture and fiber (mass ÷ specific gravity ÷ 1000) are subtracted from 1 m³ (less entrapped air) to leave the aggregate volume. The coarse aggregate volume is split across whichever of 10/20/40 mm you use, and the fine aggregate volume is split between sand and dust if you use both; each fraction converts to an SSD mass with its own specific gravity.
10. A-10 Mix proportions for trial number 1: the SSD-basis trial quantities — cement, mineral admixture, net mixing water, fine and coarse aggregate (SSD), chemical admixture, and the adopted free water-cementitious ratio.
11. A-11 Adjustment for dry aggregates: if the coarse and fine aggregate are in dry (or otherwise non-SSD) condition, each fraction's SSD mass and the design water are corrected for its actual free surface moisture versus its water absorption.
12. A-12 Mix proportions after adjustment: the final dry/field-adjusted quantities for the trial, plus the 1 : fine : coarse ratio, ready to print.

Formulas

f'ck = max(fck + 1.65S, fck + X)
Water content (raw) = [(Table 4 value − shape correction, Cl. 5.3) × (1 + 0.03 × (slump − 50)/25)] × (1 − water reduction %)
Cementitious content (raw) = adopted water ÷ adopted w/c(m)
Corrected CA volume fraction = Table 5 value + 0.01 × (0.50 − adopted ratio)/0.05
Field mass of a fraction = SSD mass × [1 + (moisture % − water absorption %)/100]

Note on the printed Annex A example: dividing 148 by 0.36 gives 411.11, which rounds to 411 by standard rounding, but the printed Annex A worked example shows this as ≈412. Since this calculator always shows the raw figure and lets you enter the adopted (rounded) value yourself, you can match either convention exactly.

Reference: IS 10262:2019 Concrete Mix Proportioning — Guidelines (Second Revision), Annex A, B and C; IS 456:2000; IS 383:2016. Durability limits and grading data shown in this app are commonly-cited defaults — verify against the current edition for your project.