IS 10262:2019 is the Indian Standard (BIS) for concrete mix proportioning - guidelines. This standard provides guidelines for proportioning concrete mixes to achieve specified requirements for workability, strength, and durability. It details a systematic, step-by-step process for concrete mix design using the properties of the constituent materials, supplemented with illustrative examples.
Provides guidelines for the proportioning of concrete mixes.
Target mean strength, water content, CA volume tables, SCM replacement and trial-mix sequencing.
| Reference | Value | Clause |
|---|---|---|
| Target mean strength — characteristic σ basis | f'ck = fck + 1.65 σ | Cl. 5.1.1 |
| Standard deviation — M10–M15 | 3.5 N/mm² (assumed) | Cl. 5.1.1 (Table 1) |
| Standard deviation — M20–M25 | 4.0 N/mm² (assumed) | Cl. 5.1.1 (Table 1) |
| Standard deviation — M30–M50 | 5.0 N/mm² (assumed) | Cl. 5.1.1 (Table 1) |
| Std. deviation — M55+ | 6.0 N/mm² | Cl. 5.1.1 (Table 1) |
| Free-water content — 20 mm aggregate, slump 50 mm | 186 kg/m³ | Cl. 5.3 (Table 4) |
| Free-water content — 10 mm aggregate, 50 mm slump | 208 kg/m³ | Cl. 5.3 (Table 4) |
| Free-water content — 40 mm aggregate, 50 mm slump | 165 kg/m³ | Cl. 5.3 (Table 4) |
| Water adjustment per 25 mm extra slump | + 3 % water | Cl. 5.3 (note 1) |
| Water adjustment for sub-angular / angular | ± 5–10 kg/m³ (rounded vs angular) | Cl. 5.3 (note 2) |
| Volume of CA — 20 mm, sand Zone II, w/c 0.50 | 0.62 (per unit total agg. vol.) | Cl. 5.5 (Table 5) |
| Volume of CA — 10 mm, sand Zone II, w/c 0.50 | 0.48 | Cl. 5.5 (Table 5) |
| CA volume adjustment per 0.05 change in w/c | ± 0.01 (decrease w/c → more CA) | Cl. 5.5 (Table 5 note) |
| Trial mix sequence — number of trials | Min 3 (one at design, ±10% binder) | Cl. 6 |
| Acceptance — average of 3 cubes | ≥ f'ck (target mean) | Cl. 6.5 |
| Min cement content — refer durability | Per IS 456 Table 5 | Cl. 4.2 / IS 456 |
| Max cement content (excl. SCMs) | 450 kg/m³ | Cl. 4.2.4 / IS 456 Cl. 8.2.4.2 |
| SCM (fly ash) replacement — typical limits | 15–35 % by mass of OPC | Cl. 4.4 / IS 1489 / IS 456 |
| GGBS replacement — typical | 25–70 % by mass of OPC | Cl. 4.4 / IS 16714 |
| Silica fume replacement — typical | 5–10 % by mass of OPC | Cl. 4.4 / IS 15388 |
BIM-relevant code. See the BIM Hub for ISO 19650, IFC, and LOD/LOIN frameworks used alongside it.
IS 10262:2019 is the Indian Standard for concrete mix proportioning — it governs how you derive the cement, water, fine aggregate, and coarse aggregate quantities needed to produce concrete of a specified grade.
Per IS 456:2000 Clause 9, design mix per IS 10262 is mandatory for M20 and above. Nominal mix (1:1.5:3 for M20, 1:1:2 for M25) is permitted only up to M20 in small works.
You use IS 10262 whenever you specify: - Structural RCC of any grade M20 or higher (buildings, bridges, foundations) - High-strength concrete (M60+) with SCM adjustments (fly ash, GGBS, silica fume) - Pumpable mix design for RMC delivery - Self-consolidating concrete (covered in IS 10262 Clause 5.7 added in 2019 revision)
Exceptions where IS 10262 alone is not enough: - Water-retaining structures — pair with IS 3370 Part 2 for crack control durability adjustments - Bridge concrete — supplement with IRC 21 or IRC 112 which specify additional bridge-specific durability requirements
IS 10262:2019 Annex A defines the design mix procedure. The 2019 revision expanded the table range to M80, added SCM guidance, and included stepped procedures for SCC and high-performance concrete.
Step 1 — Target mean strength (Clause 4.2): f_target = f_ck + 1.65 × σ, where σ is standard deviation from Table 2 (5 MPa for M30, 6 MPa for M45, 7 MPa for M55+).
Step 2 — Water-cement ratio (Table 1): bounded by the exposure class per IS 456 Table 5 (Mild 0.55, Moderate 0.50, Severe 0.45, Very Severe 0.45, Extreme 0.40).
Step 3 — Water content (Clause A-4): 186 litres/m³ for 20 mm MSA nominal mix, adjusted for workability (slump) and admixture dosage.
Step 4 — Cement content: Cement = Water / W-C ratio. Cross-check minimum cement per IS 456 Table 5 (300 kg/m³ Mild, 320 Moderate, 340 Severe, etc.).
Step 5 — Aggregate proportions (Table A-3 in 2019): volume of coarse aggregate per unit volume of total aggregate, by zone and MSA.
Step 6 — Fine aggregate volume from mass-volume balance.
Step 7 — Trial batch + strength test: 3 trial mixes, 28-day cube test per IS 516.
Step 8 — Adjust and finalise — if mean strength exceeds target by >10%, reduce cement to economise; if under target, increase cement or reduce W-C ratio.
Problem: M30 concrete for a residential RCC building in moderate exposure. OPC 43 grade, 20 mm MSA, Zone II fine aggregate, 100 mm slump, no SCM.
Step 1 — Target: f_target = 30 + 1.65 × 5 = 37.25 MPa
Step 2 — W/C ratio (Table 1): For M30 and moderate exposure, max W/C = 0.50. Use 0.45 for safety margin.
Step 3 — Water content: For 20 mm MSA, 100 mm slump: base 186 litres + 3% per 25 mm slump above 50 = 186 × 1.06 = 197 litres/m³. With superplasticizer at 0.8%, reduce by 20% → 158 litres/m³.
Step 4 — Cement: 158 / 0.45 = 351 kg/m³. Check minimum per IS 456 Table 5 (moderate = 300) — 351 > 300 ✓
Step 5 — Aggregate volume: For 20 mm MSA and Zone II fine aggregate, coarse volume = 62% of total aggregate volume (Table A-3 for 2019 revision).
Step 6 — Mass-volume balance: Volume of concrete = 1.000 m³ Volume of cement = 351 / (3.15 × 1000) = 0.111 m³ Volume of water = 158 / 1000 = 0.158 m³ Volume of air (entrained) = 0.010 m³ Volume of aggregates = 1.000 − 0.111 − 0.158 − 0.010 = 0.721 m³ Coarse aggregate volume = 0.721 × 0.62 = 0.447 m³ → mass = 0.447 × 2700 = 1,207 kg/m³ Fine aggregate volume = 0.721 × 0.38 = 0.274 m³ → mass = 0.274 × 2650 = 726 kg/m³
Final mix (kg/m³): Cement 351 · Water 158 · Coarse Aggregate 1,207 · Fine Aggregate 726 · Superplasticizer 2.8 (0.8% of cement).
Mix ratio by mass: 1 : 2.07 : 3.44 · W/C 0.45
Trial batch 28-day strength target ≥ 37.25 MPa. If first trial gives 42 MPa, reduce cement to 335 kg and retest.
1. Using nominal mix for M25+. IS 456 Clause 9.3 permits nominal mix only up to M20. M25 and above require design mix. Many site engineers still use nominal M25 as 1:1:2 — non-compliant, and 28-day cube tests often fail.
2. Ignoring minimum cement per IS 456 Table 5. Design mix may give you 280 kg/m³ for M25 in mild exposure, but IS 456 Table 5 requires minimum 300 kg/m³. Durability trumps economy. Always cross-check.
3. Wrong aggregate specific gravity assumptions. Default 2.7 for coarse and 2.65 for fine are approximations. For accurate mix design on a real project, test your source aggregates per IS 383 Clause 8 — specific gravity varies from 2.55 (granite) to 2.95 (basalt) and affects mix proportions by ~5-10%.
4. Skipping the trial batch. Design mix on paper is not enough. IS 10262 Clause 4.6 mandates trial batches with 28-day cube testing. Skipping this and going straight to site pour is how mix failures happen — often discovered only after a slab has set.
5. Not accounting for SCM interactions in 2019 revision. The 2019 update added explicit SCM adjustment factors (Clause 5.6). If you use fly ash at 20% replacement, the effective W-C ratio and strength development curves differ from pure OPC. Using the 2009 edition calculator for an SCM mix under-proportions the cement.
IS 10262:2019 is a significant revision over the 2009 edition. Key improvements: expanded M80 range, explicit SCM provisions, SCC mix design procedure, and updated aggregate proportion tables.
In field practice, the 2019 tables are noticeably more conservative than 2009 for M30-M50 mixes — expect ~5-10% higher cement content for the same grade and exposure. This reflects lessons from durability failures (chloride ingress, ASR) in projects designed per 2009 mixes.
Most Indian RMC plants transitioned to 2019-compliant mixes during 2020-2022. If you are reviewing a design signed before 2020, verify which edition was used — pre-2019 mixes may need revision for current projects, especially in Severe+ exposure zones (coastal, industrial).
For high-strength concrete M60+, IS 10262:2019 Clause 5.6 is a starting point but not sufficient — pair with ACI 211.1 or fib Model Code 2020 for detailed HSC mix design. Indian HSC projects (Delhi Metro, infrastructure PPPs) typically cite both IS 10262 and ACI 211.1 in their DBRs.
Amendment No. 1 (2023) added clarifications on fly ash and GGBS blending limits. Check for the latest amendment before design freeze.
| Parameter | IS Value | International | Source |
|---|---|---|---|
| Target Strength Formula (Typical) | f'ck = fck + 1.65 * s (where s = standard deviation) | f'cr = fc' + 1.34 * s (for >30 consecutive tests) | ACI 318-19 |
| Est. Water Content (20mm NMSA, 50mm slump) | 186 kg/m³ (for 25-50mm slump) | Approx. 193 kg/m³ (for 25-50mm slump, non-air entrained) | ACI 211.1-91 |
| Est. Entrapped Air (20mm NMSA) | 1.0% | 1.5% (Typical value for non-air-entrained) | ACI 211.1-91 |
| Basis for Fine Aggregate Proportioning | Grading Zones (I, II, III, IV) per IS 383 | Fineness Modulus (FM) | ACI 211.1-91 |
| Coarse Aggregate Volume (20mm NMSA) | 0.62 (vol of CA / vol of total agg.) for Zone II FA, w/c=0.5 | 0.64 (bulk vol of CA / vol of concrete) for FM=2.80 | ACI 211.1-91 |
| Water Adjustment for Slump | Increase water content by ~3% for every 25 mm slump increase above 50 mm. | Tables provide direct water content values for different slump ranges (e.g. 25-50mm, 75-100mm). | ACI 211.1-91 |