📅 UPDATED 2026
Mix Design Methods Comparison 2026
Complete Comparison of Major Concrete Mix Design Standards — IS 10262:2019, ACI 211.1, BS EN 206, DOE Method, Road Note 4, BIS & IRC — Formulas, Steps, Tables & Worked Examples
📄 Table of Contents
- Introduction to Concrete Mix Design Methods — Overview & Importance (2026)
- At-a-Glance Comparison Table — All Methods Side by Side
- IS 10262:2019 Method — Indian Standard (Cube Basis)
- ACI 211.1 Method — American Concrete Institute (Cylinder Basis)
- DOE Method — Department of Environment, UK
- Road Note 4 Method — UK Transport Research Laboratory
- BS EN 206 / BS 8500 Method — European Standard
- IRC Method — Indian Roads Congress (Pavement Concrete)
- Target Mean Strength Formulas — All Methods Compared
- Water-Cement Ratio Determination — Method by Method
- Water Content Tables — IS 10262 vs ACI 211.1 vs DOE
- Aggregate Proportioning Approaches — Key Differences
- Worked Example — M30 Grade Designed by Three Methods
- Which Method Should You Use? — 2026 Selection Guide
- FAQs on Mix Design Method Comparison
Introduction to Concrete Mix Design Methods — Overview & Importance (2026)
Concrete mix design is the process of selecting suitable ingredients — cement, water, fine aggregate, coarse aggregate, and admixtures — and determining their proportions to produce concrete with specified properties at minimum cost. Several internationally recognised methods exist, each developed in a different national context, using different statistical bases, test specimen types, and empirical tables. Choosing the right method is not merely a procedural choice — it determines compliance with contract specifications, approval authority requirements, and the validity of the resulting mix design report.
In 2026, six methods are in active use globally for structural and pavement concrete. The IS 10262:2019 method governs all Indian projects and is mandatory per IS 456:2000 for M30 and above. ACI 211.1 is the dominant method in the USA and internationally specified projects. The DOE Method (UK Department of Environment, published as Concrete Practice) and Road Note 4 (UK Transport Research Laboratory) were widely used in the UK and Commonwealth countries before the adoption of BS EN 206. The IRC method applies specifically to rigid pavement concrete in India.
All methods share the same underlying principle — achieving a target mean strength statistically higher than the specified characteristic strength, with adequate workability for placement, and durability for the exposure condition. They differ in: how they express strength (cube vs cylinder); how they determine water demand; how they select water-cement ratio; and how they proportion aggregates. Understanding these differences prevents design errors when working across international standards.
🔎 Key Principle Common to All Mix Design Methods (2026)
- Target Mean Strength: All methods design above the specified strength by a statistical margin (k × σ) — ensuring the characteristic strength is met with an acceptable probability of failure
- Water-Cement Ratio: All methods use w/c ratio as the primary strength-governing parameter (Abrams’ Law)
- Absolute Volume Balance: All methods sum ingredient volumes to equal 1 m³ of concrete
- Durability Constraints: All methods apply maximum w/c and minimum cement limits from exposure class requirements
- Trial Mix Validation: All methods require laboratory trial mixes before production adoption
At-a-Glance Comparison Table — All Major Mix Design Methods (2026)
The table below provides a side-by-side overview of the six principal concrete mix design methods used globally. Use this as a quick reference to identify how methods differ in their fundamental approach before studying each method in detail.
| Parameter | IS 10262:2019 (India) | ACI 211.1 (USA) | DOE Method (UK) | Road Note 4 (UK) | BS EN 206:2021 (Europe) | IRC:44 / IRC:15 (India Roads) |
|---|---|---|---|---|---|---|
| Governing Body | Bureau of Indian Standards (BIS) | American Concrete Institute | UK Dept. of Environment / BRE | UK Transport Research Lab | European Standards (CEN) | Indian Roads Congress |
| Standard Reference | IS 10262:2019 + IS 456:2000 | ACI 211.1-91 (reaffirmed 2022) + ACI 318-19 | Concrete Practice (BRE 1988 / 1997) | RRL Road Note 4, 1950 (revised) | BS EN 206:2013+A2:2021 + BS 8500 | IRC:44-2017 + IRC:15-2017 |
| Test Specimen | 150 mm cube, 28 days | 150×300 mm cylinder, 28 days | 150 mm cube, 28 days | 150 mm cube, 28 days | 150 mm cube OR 150×300 mm cyl. | 150 mm cube (flexural beam for pavements) |
| Strength Basis | Characteristic cube strength fck | Specified cylinder strength f’c | Characteristic cube strength fcu | Works cube strength | Characteristic fck (cube or cyl.) | Characteristic flexural strength (MR) |
| TMS Formula | fcr = fck + 1.65 × S | f’cr = f’c + 1.34s (or 2.33s − 3.45) | fm = fcu + k × s (k=1.64) | Works strength = fm − margin | fcm = fck + 1.48σ (or + k2) | fcr = fck + 1.65 × S (for cube basis) |
| Confidence Level | 95% (k = 1.65) | ~90% (k=1.34) and ~99% (k=2.33); both checked | 95% (k = 1.64) | Variable; typically 90% | 95% (k = 1.48, EN statistical method) | 95% (same as IS 10262) |
| w/c Ratio Method | IS 10262 Table 2 strength–w/c curve + IS 456 Table 5 durability cap | ACI 211.1 Table 6.3.4(a)/(b) empirical w/cm tables by f’cr + exposure | BRE design chart (w/c vs compressive strength by cement type) | RN4 design chart (w/c vs works cube strength) | EN 206 exposure class w/c limits + strength-derived | IS 456 Table 5 (same as IS 10262) + IRC flexural requirement |
| Water Content | IS 10262 Table 2 (slump + MSA + aggregate type) | ACI 211.1 Table 6.3.3 (slump + MSA + air) | BRE Table (slump + MSA) | RN4 Table (workability class + MSA) | EN 206 guidance + Annex F (informative) | IS 10262 Table 2 values (adopted by IRC) |
| Aggregate Proportioning | Absolute volume; CA from IS 10262 Table 3 (jc × DRBD); FA by difference | Absolute volume; CA from ACI Table 6.3.6 (jc × DRBD); FA by difference | BRE chart — % fine agg. vs w/c ratio vs MSA vs FA zone (grading curve) | RN4 chart — grading zone + workability class | Absolute volume or producer’s system; no single standard table | Absolute volume; CA by IS 10262 Table 3 |
| SD Assumed (New Source) | IS 10262 Table 1: 3.5–5.0 MPa by grade | ACI 318 fixed margins: +7/+8.3/1.1f’c+5 MPa by f’c range | BRE: 8 MPa (overall target margin) for site with no data | Variable; typically 5.5–8.5 MPa per RN4 Table 1 | Fixed k2 margin: +4 MPa (≤C35); +6 MPa (>C35) | IS 10262 Table 1 (adopted) |
| Min Records for Actual σ | ≥ 30 results | ≥ 30 results (or 15–29 with ACI correction factor) | ≥ 20 results (BRE guidance) | ≥ 40 results (RN4) | ≥ 35 results (EN 206 Cl. 8.2) | ≥ 30 results (IS 456) |
| Workability Measure | Slump (mm) — IS 1199 | Slump (inches/mm) — ASTM C143 | Slump (mm) or compacting factor — BS 1881 | Workability class (VB, CF, slump) — BS 1881 | Slump / Flow class — EN 12350 | Slump (mm) — IS 1199; VeBe for pavement |
| Current Status | Current — 2019 edition | Current — reaffirmed 2022 | Legacy — still used in practice | Legacy — largely replaced | Current — 2021 edition | Current — 2017 revision |
| Primary Application | All Indian structural concrete | US + internationally specified projects | UK practice, legacy Commonwealth projects | UK road/pavement projects (legacy) | European + UK projects post-2004 | Indian highway pavement concrete |
IS 10262:2019 Method — Indian Standard Mix Design (Cube Basis)
The IS 10262:2019 method is the primary concrete mix design procedure for all structural concrete in India. It uses 150 mm cube compressive strength as the basis, follows the absolute volume method for proportioning, and is complemented by IS 456:2000 for durability requirements. The 2019 edition updated water content tables, standard deviation values, and formally recognised manufactured sand (M-Sand) and supplementary cementitious materials (SCMs).
IS 10262:2019 — Step-by-Step Procedure
- 1Stipulate Data: Specify fck (characteristic cube strength), exposure class (IS 456 Table 3), workability (slump mm), maximum aggregate size, cement type and grade, aggregate specific gravity and absorption, and SCM details if applicable.
- 2Target Mean Strength (TMS): Calculate fcr = fck + 1.65 × S, where S is from IS 10262 Table 1 (assumed, for new sources) or actual calculated σ (when ≥30 results available).
- 3Water-Cement Ratio: Read w/c from IS 10262 Figure 1 / Table 2 strength–w/c curves for the cement grade and fcr. Cap at IS 456 Table 5 maximum for the exposure class. Use the lower value.
- 4Water Content: Read design water content from IS 10262 Table 2 for your slump and MSA combination (crushed aggregate values). Reduce by 10 L/m³ for rounded aggregate; adjust for admixture water reduction.
- 5Cement Content: Cement = Water / w/c. Check ≥ IS 456 Table 5 minimum and ≤ 450 kg/m³ maximum. Apply fly ash k-value (0.25) per Cl. 5.7 if SCMs are used.
- 6Coarse Aggregate Content: From IS 10262 Table 3 — read volume fraction (jc) for your MSA and FA zone. CA mass = jc × Dry-Rodded Bulk Density (DRBD) of CA.
- 7Fine Aggregate Content: By absolute volume balance: V_FA = 1.0 − V_cement − V_water − V_CA − V_SCM − V_air. FA mass = V_FA × SG_FA × 1000.
- 8Trial Mixes & Adjustment: Conduct minimum 3 trial mixes per IS 10262 Cl. 9 at design w/c and ±10% variations. Validate TMS and workability. Adjust and finalise.
IS 10262:2019 — KEY FORMULAS:
Target Mean Strength: fcr = fck + 1.65 × S (Cl. 5.3.2)
Cement Content: C = W / (w/c)
Effective w/c (SCM): w/c_eff = W / (C + k_FA × FA_mass) ; k_FA = 0.25
FA Volume: V_FA = 1.0 − (C/3150) − (W/1000) − (CA/SG_CA/1000) − V_air
FA Mass: FA = V_FA × SG_FA × 1000
Assumed S (IS 10262 Table 1):
M10–M15 → S = 3.5 MPa (Margin = 5.8 MPa)
M20–M25 → S = 4.0 MPa (Margin = 6.6 MPa)
M30–M55 → S = 5.0 MPa (Margin = 8.3 MPa)
M60+ → By trial mix (typically 6.0–8.0 MPa)
📋 IS 10262:2019 vs IS 10262:2009 — Key Changes
Updated Table 1: Standard deviation values revised for all grade ranges; new values for M55 and M60 added.
Updated Table 2: Water content values revised to reflect current aggregate types including M-Sand; 10 mm MSA values corrected.
SCM Guidance: Fly ash efficiency factor (k = 0.25) formally codified in Cl. 5.7; GGBS and silica fume guidance expanded.
M-Sand Recognised: IS 383:2016-compliant manufactured sand formally included in Table 2 and Table 3 lookup.
SCC Annex: New Annex for self-compacting concrete mix design guidance added.
ACI 211.1 Method — American Concrete Institute Mix Design (Cylinder Basis)
The ACI 211.1-91 (reaffirmed 2022) method is the standard mix design procedure in the United States and widely adopted for internationally specified projects. It uses 150×300 mm cylinder compressive strength, and combines empirical tables (water content, w/c, aggregate volume) with the absolute volume method. Per ACI 318-19, the required average cylinder strength (f’cr) accounts for statistical variability using two simultaneous criteria.
ACI 211.1 — Step-by-Step Procedure
- 1Required Average Strength (f’cr): If SD known (≥30 tests): f’cr = larger of (f’c + 1.34s) or (f’c + 2.33s − 3.45). If SD unknown: f’cr = f’c + 7.0 MPa (f’c < 21), or f’c + 8.3 MPa (21–35 MPa), or 1.10f’c + 5.0 MPa (f’c > 35 MPa).
- 2Select w/cm Ratio: From ACI 211.1 Table 6.3.4(a) by f’cr; cross-check with ACI 318 Table 26.4.2 maximum w/cm for exposure category. Use the lower value.
- 3Select Air Content: From ACI 318 Table 26.4.3.1 by exposure category and MSA. For non-air-entrained concrete, use ACI 211.1 Table 6.3.3 entrapped air values.
- 4Select Water Content: From ACI 211.1 Table 6.3.3 by slump and MSA (separate columns for air-entrained and non-air-entrained). Adjust for admixtures.
- 5Cement Content: Cement = Water content / w/cm ratio. Check against ACI 318 minimum requirements for exposure category.
- 6Coarse Aggregate Volume: From ACI 211.1 Table 6.3.6 — volume of dry-rodded CA per unit volume of concrete (jc) by MSA and FM of fine aggregate. CA mass = jc × DRBD.
- 7Fine Aggregate Content: By absolute volume: V_FA = 1.0 − V_cement − V_water − V_CA − V_air − V_admixtures. FA mass = V_FA × SG_FA × 62.4 (lb/ft³) or × 1000 (kg/m³).
- 8Moisture Adjustment & Trial Mix: Adjust batch water for aggregate moisture. Conduct trial batches and adjust w/cm to achieve f’cr. Minimum three trials per ACI 301.
ACI 211.1 — KEY FORMULAS (SI UNITS):
Required Average Strength (with known SD, ≥30 tests):
f’cr = f’c + 1.34 × s [Eq. 1 — ACI 318 §26.4.3.1]
f’cr = f’c + 2.33 × s − 3.45 [Eq. 2]
Use: LARGER of Eq. 1 and Eq. 2
Required Average Strength (without SD data):
f’c < 21 MPa → f’cr = f’c + 7.0 MPa
21–35 MPa → f’cr = f’c + 8.3 MPa
f’c > 35 MPa → f’cr = 1.10 × f’c + 5.0 MPa
Cement Content: C = W / (w/cm)
FA Volume: V_FA = 1 − V_C − V_W − V_CA − V_air − V_admix
FA Mass: FA = V_FA × SG_FA × 1000 kg/m³
Cylinder → Cube Conversion (approx.):
Cube fck ≈ Cylinder f’c × 1.25 (for normal concrete)
📌 Critical Difference — ACI Uses Two f’cr Equations Simultaneously
Unlike IS 10262 which uses a single formula (fck + 1.65×S), ACI 318-19 requires calculating both Equation 1 (f’c + 1.34s) and Equation 2 (f’c + 2.33s − 3.45) and adopting the larger result. This dual-criteria approach provides combined protection against both individual low results and low running averages. For concrete with s = 4.0 MPa and f’c = 30 MPa (cylinder): Eq.1 = 35.4 MPa; Eq.2 = 35.9 MPa → adopt 35.9 MPa. The IS 10262 equivalent (cube) = 38.3 MPa — which converts to approximately 30.6 MPa cylinder, so ACI is more conservative at this strength level.
DOE Method — Department of Environment, UK (BRE Concrete Practice)
The DOE method was developed by the UK Building Research Establishment (BRE) and published as Design of Normal Concrete Mixes (1975, revised 1988 and 1997). Although largely superseded by BS EN 206 in the UK, the DOE method remains influential in many Commonwealth countries and is still referenced in some project specifications. It uses graphical design charts rather than lookup tables, and its approach to fine aggregate proportioning via a “% passing 600 µm” parameter is distinctive.
DOE Method — Step-by-Step Procedure
- 1Target Mean Strength: fm = fcu + k × s, where fcu is the characteristic cube strength, k = 1.64 (for 95% confidence, DOE uses 1.64 rather than 1.65 per a slightly different statistical table), and s is the standard deviation. If no data: use a margin of 8.0 MPa (for established concrete production) or higher for new sources.
- 2Free Water-Cement Ratio: From BRE Design Chart 2 — plot target mean compressive strength against w/c ratio for the cement strength class (or use OPC test result). Read off the free w/c. Compare with durability limits; adopt the lower.
- 3Free Water Content: From BRE Table 3 by slump class (0–10mm, 10–30mm, 30–60mm, 60–180mm) and maximum aggregate size (10, 20, 40 mm). Values for uncrushed and crushed aggregate given separately.
- 4Cement Content: C = W / (w/c). Check IS exposure or BS 8110 minimum cement limits. Check maximum cement (550 kg/m³ per BRE guidance).
- 5Total Aggregate Content: From BRE Figure 4 (or equivalent table) — wet density of fully compacted concrete vs. free w/c ratio vs. cement content. Total Agg. = Wet Density − Cement − Water.
- 6Fine Aggregate Proportion: From BRE Figure 5 — % fine aggregate by mass vs. w/c ratio vs. MSA vs. % passing 600 µm sieve (C-value). Read FA% and compute: FA = FA% × Total Agg.; CA = Total Agg. − FA.
- 7Trial Mix Verification: Prepare trial mix, measure slump, cast specimens for 7-day and 28-day cube tests. Adjust water content and FA% as needed.
DOE METHOD — KEY FORMULAS:
Target Mean Strength: fm = fcu + 1.64 × s (k = 1.64 for 5% defective)
Standard margin (no data, established production): +8 MPa
Standard margin (no data, new site): +10 to +12 MPa
Cement Content: C = W / (w/c)
Total Aggregate Mass: TA = Wet Concrete Density − C − W
Wet density from BRE Figure 4:
≈ 2400 + 60 × (2.65 − w/c) kg/m³ (crude approximation for SSD agg.)
Fine Aggregate: FA = (FA%) × TA
Coarse Aggregate: CA = TA − FA
FA% determined from BRE Figure 5:
Depends on: w/c ratio, MSA (10/20/40 mm), % passing 600 µm (C-value)
⚠️ DOE Method — Important Limitations in 2026
Legacy Graphical Method: The DOE method relies on printed design charts. Digital interpretation of these charts introduces variability. Some values require interpolation which, if done inaccurately, can lead to mix design errors of ±15–20 kg/m³ in cement content.
No Coverage of HSC: The BRE design charts cover w/c ratios of 0.35–0.75. High-strength concrete (M60+) with w/c below 0.35 is outside the original chart range.
C-Value Requirement: The DOE method’s fine aggregate proportioning uses % passing 600 µm (C-value) — a parameter not routinely reported in Indian IS 383 sieve analysis reports, making direct adoption on Indian projects difficult.
Road Note 4 Method — UK Transport Research Laboratory (Road Pavement Concrete)
Road Note 4 (RN4) was published by the UK Road Research Laboratory (now Transport Research Laboratory) in 1950 and revised through the 1970s. It was the principal mix design method for road pavement concrete in the UK and many Commonwealth countries. While largely replaced by BS EN 206 and the Highways England manual in the UK, it remains referenced in some Commonwealth project specifications and provides a useful historical perspective on pavement concrete design methodology.
Road Note 4 — Distinctive Features vs Other Methods
📌 Works Cube Strength Concept
RN4 uses “works cube strength” — the actual mean strength achieved during production — rather than the characteristic strength concept used by IS 10262 and ACI 211.1. The target works cube strength is set equal to the specified strength plus a margin that accounts for production variability.
Works Strength = Specified Strength + Margin
Margin = k × s (typically 5.5–8.5 MPa for site production)
📌 Workability Classes
RN4 classifies workability into four categories rather than continuous slump: Very Low (VB ≥ 12 sec), Low (VB 3–12 sec), Medium (slump 25–75 mm), and High (slump > 75 mm). Water content is then read from RN4 tables for each workability class and aggregate size.
- 1Target Works Cube Strength: Works strength = Specified strength + Margin. Margin determined from RN4 Table 1 by degree of control (Very Good / Good / Fair / Poor) — typically 5.5 MPa (very good, well-controlled) to 10 MPa (fair control).
- 2Free Water-Cement Ratio: From RN4 design curves (similar to DOE) — plot works cube strength vs w/c for OPC. Read off the required w/c. Typical pavement concrete: w/c 0.40–0.55.
- 3Water Content: From RN4 Table 2 by workability class and MSA. Pavement concrete typically requires Very Low or Low workability (VB ≥ 3 sec) — water demand correspondingly lower.
- 4Cement Content: C = W / (w/c). For road pavement concrete: minimum 300 kg/m³; typical 330–380 kg/m³.
- 5Aggregate Grading: RN4 specifies combined aggregate grading zones for road concrete using grading envelopes. The proportion of fine to coarse aggregate is selected to achieve a combined grading within the specified envelope.
- 6Trial Mix: Prepare trial mix. Measure VeBe time or slump, density, and cast cubes for 7d and 28d testing. Pavement concrete frequently requires additional flexural strength (MR) testing per BS 1881 or IS 516.
ROAD NOTE 4 — KEY RELATIONSHIPS:
Works Strength: fworks = fspecified + Margin (from RN4 Table 1)
Degree of Control → Margin (MPa):
Very Good → 5.5
Good → 7.0
Fair → 8.5
Poor → 10.0+
Cement Content: C = W / (w/c)
Pavement Concrete Strength Relationship:
MR (Modulus of Rupture) ≈ fcu^0.5 × 0.7 [approximate, MPa]
Typical target: MR = 4.5 MPa min. for heavy traffic pavement
→ Requires fcu ≈ (4.5/0.7)² ≈ 41 MPa cube (approximate)
BS EN 206 / BS 8500 Method — European Standard Concrete Specification (2026)
BS EN 206:2013+A2:2021 and the complementary BS 8500:2015+A2:2019 (UK National Annex) form the current European and UK concrete specification framework. Unlike IS 10262 and ACI 211.1 which are mix design procedure standards, EN 206 is a concrete specification standard — it defines how to specify concrete by performance and composition requirements rather than prescribing a step-by-step proportioning procedure.
EN 206 Approach — Specification, Not Prescription
EN 206 recognises two routes for concrete specification:
- Designed Concrete: Specifier states the performance requirements (fck, exposure class, max w/c, min cement, max aggregate size, consistency class). The producer is responsible for selecting proportions to meet these requirements using their own proven mix design procedure.
- Prescribed Concrete: Specifier states the composition (cement content, water content, aggregate type) and the producer is responsible only for matching the specified composition — not for achieving any minimum strength.
BS EN 206:2021 — TARGET MEAN STRENGTH FORMULA:
When σ is established (≥35 results):
fcm = fck + 1.48 × σ [Cl. 8.2.1, Table 14]
When σ is NOT yet established (initial production):
fcm = fck + k2
where k2 = +4 MPa for fck ≤ C35/45
+6 MPa for fck > C35/45
Exposure Class — Minimum Requirements (BS 8500 / EN 206):
XC1 (dry/permanently wet) → C16/20 min, w/c ≤ 0.70
XC2 (wet, rarely dry) → C20/25 min, w/c ≤ 0.65
XC3 (moderate humidity) → C30/37 min, w/c ≤ 0.55
XC4 (cyclic wet/dry) → C30/37 min, w/c ≤ 0.50
XD1 (moderate chloride) → C30/37 min, w/c ≤ 0.55
XD2 (wet, rarely dry chloride) → C35/45 min, w/c ≤ 0.45
XS3 (tidal/splash/spray) → C35/45 min, w/c ≤ 0.45
XF4 (high freeze-thaw + salt) → C30/37 + air entrain, w/c ≤ 0.45
Notation: C20/25 = fck,cylinder / fck,cube (MPa)
Cube to Cylinder: fck,cyl ≈ 0.82 × fck,cube (for C20–C50)
📋 EN 206 Concrete Family / Deemed-to-Satisfy Approach
BS 8500 introduces the “deemed-to-satisfy” concept — pre-approved concrete compositions for specific exposure classes and intended uses. A contractor can specify a “Designated Mix” (e.g. RC30/37 for reinforced concrete in XC1/XC2) and the producer supplies a proven mix without individual design approval. This approach is efficient for routine construction but requires that the producer’s mix is pre-qualified through a factory production control (FPC) scheme — typically third-party certified to BS EN 206 Cl. 9.
IRC Method — Indian Roads Congress Pavement Concrete Design (2026)
The Indian Roads Congress (IRC:44-2017 and IRC:15-2017) governs mix design for rigid pavement concrete in India. The IRC method essentially follows IS 10262:2019 for proportioning calculations but adds pavement-specific requirements: flexural strength (Modulus of Rupture, MR) as a primary design criterion, VeBe time for workability of stiff paving mixes, and MORTH (Ministry of Road Transport and Highways) specification compliance.
| IRC Parameter | Requirement | Test Method | Standard |
|---|---|---|---|
| Min. Flexural Strength (MR) | ≥ 4.5 MPa at 28 days (third-point loading) | IS 516 / ASTM C78 | IRC:15-2017 Cl. 5.3 |
| Equivalent Cube Strength | Typically M40 (fck = 40 MPa) for NHs; M35 for SH | IS 516 | MORTH Cl. 602.3 |
| w/c Ratio (Max) | 0.40 for heavy traffic; 0.45 for other roads | Calculated | IRC:44-2017 |
| Cement Content (Min) | 360 kg/m³ (NH); 320 kg/m³ (other) | Calculated | MORTH Table 1700-3 |
| Workability (Pavement) | VeBe: 5–10 seconds OR slump 20–40 mm | IS 1199 / BS 1881 | IRC:15-2017 Cl. 8 |
| Air Entrainment (Cold Regions) | 4–6% (for frost-exposed pavements) | IS 1199 Part 7 | IRC:44-2017 Cl. 5.7 |
| Aggregate (LA Abrasion) | ≤ 35% loss (coarse aggregate) | IS 2386 Part IV | MORTH Cl. 1000 |
| Aggregate Absorption | ≤ 2.0% (coarse); ≤ 3.0% (fine) | IS 2386 Part III | IS 383:2016 |
IRC:44-2017 — RELATIONSHIP BETWEEN fck AND MR:
Approximate relationship (IS 456:2000 Cl. 6.2.2):
fct = 0.7 × √fck (direct tensile strength, MPa)
For flexural (MR), empirical relationship:
MR ≈ 0.7 × √fck to 0.85 × √fck (MPa, depending on aggregate)
Example — Target MR = 4.5 MPa:
4.5 = 0.7 × √fck → fck = (4.5/0.7)² = 41.3 MPa → Use M40 (fck = 40 MPa)
OR
4.5 = 0.85 × √fck → fck = (4.5/0.85)² = 28.0 MPa → Use M30
Note: IRC:15-2017 specifies minimum M40 for National Highways regardless
of flexural calculation, as a durability and performance requirement.
Target Mean Strength Formulas — All Methods Compared (2026)
All mix design methods require designing to a higher-than-specified strength to statistically guarantee the characteristic strength. The following table compares TMS calculations for a nominal M30 / C25/30 grade across all methods, assuming equivalent production control (good to very good quality).
| Method | Specimen | Specified Strength | σ / s Assumed | TMS Formula | TMS Result | Margin over fck |
|---|---|---|---|---|---|---|
| IS 10262:2019 | 150 mm cube | fck = 30 MPa | S = 5.0 MPa (Table 1) | fcr = 30 + 1.65×5.0 | 38.3 MPa | +8.3 MPa |
| ACI 211.1 / ACI 318 | 150×300 mm cyl. | f’c = 24 MPa (≈30 cube) | No data → use table | f’cr = 24 + 8.3 | 32.3 MPa cyl. ≈ 40.4 MPa cube | +8.3 MPa cyl. / +10.4 cube |
| ACI (with known SD, s=4.5 MPa) | 150×300 mm cyl. | f’c = 24 MPa | s = 4.5 MPa | Eq.1: 24+1.34×4.5=30.0; Eq.2: 24+2.33×4.5−3.45=31.0 | 31.0 MPa cyl. ≈ 38.8 MPa cube | +7.0 MPa cyl. / +8.8 cube |
| DOE Method (BRE) | 150 mm cube | fcu = 30 MPa | s = 5.0 MPa (site) | fm = 30 + 1.64×5.0 | 38.2 MPa | +8.2 MPa |
| DOE (no data — new site) | 150 mm cube | fcu = 30 MPa | Assumed +10 margin | fm = 30 + 10 | 40.0 MPa | +10.0 MPa |
| Road Note 4 | 150 mm cube | f = 30 MPa | Good control margin | fworks = 30 + 7.0 | 37.0 MPa | +7.0 MPa |
| BS EN 206:2021 (initial) | 150 mm cube | fck = 30 MPa (C25/30) | k2 = +4 (≤C35) | fcm = 30 + 4 | 34.0 MPa | +4.0 MPa |
| BS EN 206:2021 (established, σ=5.0) | 150 mm cube | fck = 30 MPa | σ = 5.0 MPa (≥35 results) | fcm = 30 + 1.48×5.0 | 37.4 MPa | +7.4 MPa |
📋 Why EN 206 Initial Production Margin (+4 MPa) is Lower Than IS 10262 (+8.3 MPa)
The EN 206 initial production margin (k2 = +4 MPa for C ≤ C35) appears very low compared to IS 10262’s +8.3 MPa for M30. However, this comparison is misleading for two reasons. First, EN 206 initial production concrete must be produced under a certified Factory Production Control (FPC) scheme — the concrete producer has established controls that justify a lower margin. Second, once ≥35 results are accumulated, the EN 206 established production margin (1.48×σ) is essentially comparable to IS 10262 (1.65×S) for the same actual σ value. The EN 206 factor 1.48 vs IS 1.65 reflects slightly different statistical methods but both target 5% defect probability.
Water-Cement Ratio Determination — Method by Method Comparison (2026)
The water-cement ratio is the single most important parameter in any mix design method — it governs strength (Abrams’ Law), durability (permeability), and ultimately cement content. The following table shows how each method arrives at the design w/c ratio for an equivalent M30 / C25/30 / f’c=24 MPa grade.
| Method | How w/c is Found | w/c from Strength (M30 equiv.) | Durability Cap | Adopted w/c | Governs |
|---|---|---|---|---|---|
| IS 10262:2019 | IS 10262 Table 2 / Figure 1 strength–w/c curve for cement grade and fcr = 38.3 MPa | 0.48 – 0.52 (OPC 53) | IS 456 Table 5: Moderate ≤ 0.50 | 0.48 – 0.50 | Strength or Durability |
| ACI 211.1 | ACI 211.1 Table 6.3.4(a) — f’cr = 32.3 MPa (cyl.) interpolated | 0.48 – 0.52 | ACI 318 Table 26.4.2: varies by exposure category | 0.48 – 0.52 | Strength (similar result) |
| DOE Method | BRE Design Chart 2 — plot fm = 38.2 MPa, read off w/c for OPC type | 0.50 – 0.55 | BS 8110 Table 3.3 / BS EN 206 | 0.50 – 0.55 | Strength (slightly more conservative charts) |
| Road Note 4 | RN4 design curve — plot fworks = 37 MPa | 0.50 – 0.55 | Per specification | 0.50 – 0.55 | Strength |
| BS EN 206:2021 | Producer’s own proven relationship (no single standard chart); or empirical table per national annex | Producer-determined | EN 206 Table 1 exposure class w/c: XC3 ≤ 0.55; XD1 ≤ 0.55 | Per producer’s system | Durability (exposure-driven) |
| IRC:44-2017 | IS 10262 Figure 1 (same as IS method) | 0.45 – 0.48 (M40 typical) | IRC:44 max 0.40 (NH) | 0.40 | Durability (always governs for NH) |
Water Content Tables — IS 10262 vs ACI 211.1 vs DOE Method Compared (2026)
Design water content — the free water per cubic metre of concrete at the specified slump — varies between methods due to different empirical databases and aggregate assumptions. The following tables allow direct comparison for the most common combination (20 mm MSA, crushed aggregate).
Water Content at 75 mm Slump, Crushed Aggregate — All Methods (L/m³)
| Maximum Aggregate Size | IS 10262:2019 Table 2 (L/m³) | ACI 211.1 Table 6.3.3 (L/m³) | DOE Method Table 3 (L/m³) | Rounded vs Crushed Adjustment |
|---|---|---|---|---|
| 10 mm | 208 | 228 | 225 | IS: −10 L/m³; ACI: −18 L/m³; DOE: −15 L/m³ |
| 20 mm | 186 | 199 | 195 | IS: −10 L/m³; ACI: −18 L/m³; DOE: −15 L/m³ |
| 40 mm | 165 | 181 | 180 | IS: −10 L/m³; ACI: −18 L/m³; DOE: −15 L/m³ |
Water Content Variation with Slump — 20 mm MSA, Crushed Aggregate (L/m³)
| Slump (mm) | IS 10262:2019 (L/m³) | ACI 211.1 (L/m³) | DOE Method (L/m³) | Notes |
|---|---|---|---|---|
| 25 – 50 | 172 – 178 | 181 | 175 – 180 | Low workability — precast, pavement |
| 50 – 75 | 178 – 186 | 199 | 185 – 195 | Standard structural concrete |
| 75 – 100 | 186 – 194 | 199 – 207 | 195 – 205 | General structural, beams |
| 100 – 150 | 194 – 208 | 207 – 216 | 205 – 215 | Pumped, congested reinforcement |
| 150 – 200 | 208 – 220 | 216+ | 215+ | Piling, tremie, underwater |
⚠️ Why ACI Water Content Values Are Higher Than IS 10262 (2026)
Different reference aggregate: ACI 211.1 Table 6.3.3 values are calibrated to US aggregates (typically rounded gravel is the dominant type in the ACI database). IS 10262 Table 2 is calibrated to Indian crushed stone. The IS “crushed aggregate” values are already higher than IS “rounded aggregate” values, but still 10–20 L/m³ below ACI crushed values — reflecting inherent differences between empirical databases.
Practical implication: If you apply ACI water content values to an Indian project and use IS 10262 cement content formula, the resulting cement content will be 25–45 kg/m³ higher than necessary — a significant cost and sustainability impact. Always use the water content table matched to your design method.
Aggregate Proportioning Approaches — Key Differences Between Methods (2026)
How each method determines the split between coarse and fine aggregate is one of the most significant practical differences. The table below compares the approach, the key parameter, and the result for a 20 mm MSA, Zone II sand mix at 0.50 w/c ratio.
| Method | Approach | Key Parameter | CA Determination | FA Determination | Advantage |
|---|---|---|---|---|---|
| IS 10262:2019 | Absolute Volume — empirical jc table | jc (vol. fraction of CA) from IS 10262 Table 3 by MSA + FA zone | CA = jc × DRBD (kg/m³) | By abs. volume balance (residual) | Simple; well-suited to Indian crushed aggregate; accounts for FA zone |
| ACI 211.1 | Absolute Volume — empirical jc table | jc from ACI Table 6.3.6 by MSA + FM of fine agg. (fineness modulus) | CA = jc × DRBD (kg/m³) | By abs. volume balance (residual) | Uses FM — more sensitive to exact sand grading; widely adopted internationally |
| DOE Method | Graphical — total agg. density chart + % FA chart | % passing 600 µm (C-value); w/c ratio; MSA | FA% from BRE Chart 5; CA = Total − FA | FA% determined first; CA is residual | Explicitly links FA grading to FA%; catches coarse/fine sand differences well |
| Road Note 4 | Grading envelope approach — combined aggregate | Combined aggregate grading zone and workability class | Grading zones specify permissible FA/CA split range | Both CA and FA within grading envelope | Ensures combined grading is well-suited for pavement — minimises segregation |
| BS EN 206 | Producer’s proven system — no single prescribed method | Producer’s relationship database | Producer discretion within FPC system | Producer discretion | Flexibility for producer to optimise for their specific aggregates |
| IRC:44-2017 | Absolute Volume (same as IS 10262) | IS 10262 Table 3 jc values | CA = jc × DRBD | By abs. volume balance | Consistent with IS 10262; familiar to Indian engineers |
Worked Example — M30 Grade Concrete Designed by Three Methods Compared (2026)
The following example designs M30 (fck = 30 MPa cube) concrete for moderate exposure, 75 mm slump, 20 mm MSA, crushed aggregate, OPC 53 Grade, using IS 10262:2019, ACI 211.1, and the DOE Method. The same aggregate properties are used throughout: CA SG = 2.68, FA SG = 2.65, CA absorption = 0.60%, FA absorption = 1.20%, CA DRBD = 1450 kg/m³, FA Zone II.
COMMON INPUTS FOR ALL THREE METHODS:
Specified strength: fck = 30 MPa (cube) / f’c ≈ 24 MPa (cylinder)
Exposure: Moderate (IS) / Exposure Category B1 (ACI) / XC3 (EN)
Slump: 75 mm
MSA: 20 mm (crushed)
Cement: OPC 53 Grade, SG = 3.15
CA SG: 2.68 | CA Absorption: 0.60%
FA SG: 2.65 | FA Absorption: 1.20%
CA DRBD: 1450 kg/m³
FA Zone: Zone II (IS) / FM = 2.60 (ACI)
Entrapped Air: 1.5%
No admixture (for comparison clarity)
METHOD 1 — IS 10262:2019:
Step 1 TMS: fcr = 30 + 1.65 × 5.0 = 38.25 MPa
Step 2 w/c: From IS 10262 Table 2/Figure 1, OPC 53, fcr=38.25 → w/c = 0.49
IS 456 max (Moderate) = 0.50 → adopt w/c = 0.49
Step 3 Water: IS 10262 Table 2: 20mm MSA, 75mm slump → W = 186 L/m³
Step 4 Cement: C = 186 / 0.49 = 380 kg/m³ (> IS 456 min 300 ✓; < 450 ✓)
Step 5 CA: jc = 0.64 (Table 3, 20mm, Zone II) → CA = 0.64×1450 = 928 kg
CA vol = 928/(2.68×1000) = 0.346 m³
Step 6 FA: V_FA = 1.0 − 380/3150 − 186/1000 − 0.346 − 0.015
= 1.0 − 0.121 − 0.186 − 0.346 − 0.015 = 0.332 m³
FA = 0.332 × 2.65 × 1000 = 880 kg/m³
Check: Total = 0.121+0.186+0.346+0.332+0.015 = 1.000 ✓
RESULT (IS 10262): C=380, W=186, CA=928, FA=880 kg/m³
METHOD 2 — ACI 211.1:
Step 1 f'cr: No SD data: f'c=24 MPa → f'cr = 24 + 8.3 = 32.3 MPa (cyl.)
Step 2 w/cm: ACI Table 6.3.4(a): f'cr=32.3 MPa → w/c ≈ 0.54
ACI 318 Table 26.4.2 (Moderate) → no explicit cap for B1; adopt 0.54
Step 3 Water: ACI Table 6.3.3: 20mm MSA, 75mm slump, non-air-entrained → W = 199 L/m³
Step 4 Cement: C = 199 / 0.54 = 369 kg/m³
Step 5 CA: ACI Table 6.3.6: 20mm MSA, FM=2.60 → jc = 0.64 (same as IS here)
CA = 0.64 × 1450 = 928 kg/m³
Step 6 FA: V_FA = 1.0 − 369/3150 − 199/1000 − 0.346 − 0.015
= 1.0 − 0.117 − 0.199 − 0.346 − 0.015 = 0.323 m³
FA = 0.323 × 2.65 × 1000 = 856 kg/m³
RESULT (ACI 211.1): C=369, W=199, CA=928, FA=856 kg/m³
METHOD 3 — DOE Method:
Step 1 TMS: fm = 30 + 1.64×5.0 = 38.2 MPa
Step 2 w/c: BRE Chart 2, OPC type, fm=38.2 MPa → w/c ≈ 0.50
Step 3 Water: BRE Table 3: 20mm MSA, 60–180mm slump → W = 195 L/m³ (crushed)
Step 4 Cement: C = 195 / 0.50 = 390 kg/m³
Step 5 Total Agg.: BRE Fig.4: wet density ≈ 2390 kg/m³
TA = 2390 − 390 − 195 = 1805 kg/m³
Step 6 FA%: BRE Fig.5: w/c=0.50, 20mm MSA, C-value (% pass 600µm ≈ 55%) → FA% = 38%
FA = 0.38 × 1805 = 686 kg/m³
CA = 1805 − 686 = 1119 kg/m³
RESULT (DOE): C=390, W=195, CA=1119, FA=686 kg/m³
| Output Parameter | IS 10262:2019 | ACI 211.1 | DOE Method | Key Reason for Difference |
|---|---|---|---|---|
| TMS (MPa, cube) | 38.25 | ≈40.4 (cube equiv.) | 38.2 | ACI no-data margin larger for cylinder basis |
| w/c Ratio | 0.49 | 0.54 | 0.50 | ACI cylinder basis allows slightly higher w/c for same cube TMS |
| Water (L/m³) | 186 | 199 | 195 | ACI water table calibrated to US aggregates (higher baseline) |
| Cement (kg/m³) | 380 | 369 | 390 | Lower ACI cement due to higher w/c offsetting higher water |
| Coarse Agg. (kg/m³) | 928 | 928 | 1119 | DOE total aggregate approach gives more CA; IS/ACI jc method identical here |
| Fine Agg. (kg/m³) | 880 | 856 | 686 | DOE higher CA means lower FA; IS/ACI absolute volume gives higher FA |
| Est. Unit Weight (kg/m³) | 2374 | 2352 | 2390 | Similar across methods; DOE slightly higher due to more CA |
| FA/Total Agg. Ratio | 49% | 48% | 38% | DOE’s C-value based FA% produces more CA-rich mix for this sand |
🔎 Key Takeaway from the Worked Example
Cement content: IS 10262 gives 380 kg/m³, ACI gives 369 kg/m³, DOE gives 390 kg/m³ — a spread of ±21 kg/m³ for nominally the same grade and exposure. This difference stems almost entirely from different water content tables and different approaches to w/c-strength relationships, not from a fundamentally different design philosophy.
Aggregate split: The DOE method produces a dramatically different FA/CA split (38% FA vs 49% FA for IS/ACI) for this example. This reflects the DOE’s C-value based approach using % passing 600 µm as the FA proportion determinant — a parameter that is particularly sensitive to sand grading characteristics.
For practice: Use IS 10262:2019 for all Indian structural projects — it is the only method legally recognised by IS 456:2000 and accepted by Indian approval authorities. Use ACI 211.1 for internationally specified projects requiring cylinder basis. Never mix water content tables from one method with strength tables from another — this is a common and dangerous design error.
Which Mix Design Method Should You Use? — 2026 Selection Guide
The correct method to use is almost always determined by the project location, governing authority, and client/contract specification. The following guide helps identify the correct standard for common project scenarios.
| Project Scenario | Recommended Method | Governing Authority | Submission Format | Notes |
|---|---|---|---|---|
| Indian building / infrastructure (general) | IS 10262:2019 | BIS / State PWD / CPWD | IS 10262 Annex B format | Mandatory for M30+; preferred for all grades |
| Indian National Highway concrete pavement | IRC:44-2017 + IS 10262 | NHAI / MoRTH / IRC | MORTH format + IRC annex | MR ≥ 4.5 MPa; w/c ≤ 0.40 for NH |
| US-specified project (any country) | ACI 211.1 | ACI / State DOT / ASTM | ACI 211.1 format; cylinder basis | f’cr per ACI 318-19; w/cm per exposure category |
| UK or European project | BS EN 206 + BS 8500 | Highways England / BSI / CEN | Conformity certificate per EN 206 Cl. 11 | FPC certification required; exposure class system |
| Australian project | AS 1379:2007 | Standards Australia | AS 1379 format; cylinder basis | f’cr = f’c + 1.65s; similar to IS 10262 approach |
| Legacy UK / Commonwealth project (historical spec) | DOE / Road Note 4 | Per specification | BRE / TRL format | Verify if current EN 206 is acceptable as equivalent |
| High-strength concrete M60+ (any country) | IS 10262:2019 + ACI 363R | Project-specific; engineer approval | Full HSC mix design report + trial data | Trial mixes mandatory; assumed SD not applicable; specialist review |
| Self-Compacting Concrete (SCC) | IS 10262 Annex + EFNARC | Per project specification | SCC-specific report including rheology tests | Additional tests: flow, T50, L-box, V-funnel, segregation resistance |
| Recycled Aggregate Concrete (RAC) | IS 16714:2018 + IS 10262 | BIS / Engineer approval | IS 10262 format with IS 16714 compliance annex | Max 30% RCA replacement; higher absorption correction essential |
⚠️ Never Mix Parameters from Different Methods
A common and dangerous error: Using ACI 211.1 water content tables with IS 10262 strength–w/c curves, or using DOE target mean strength with IS 10262 aggregate tables. Each method is a self-consistent system — its tables, charts, and formulas are calibrated together. Mixing parameters from different methods invalidates the design and can produce unsafe concrete without any visible calculation error.
Cylinder vs Cube: Never specify a cylinder f’c value on an IS 10262 design form, or enter a cube fck value into an ACI 211.1 table without proper conversion. The standard conversion (cube ≈ 1.25 × cylinder) is approximate and varies with strength level — always use the correct basis for your chosen method from start to finish.
FAQs on Mix Design Method Comparison — Quick Reference (2026)
Q1: Which concrete mix design method gives the lowest cement content for M30 grade?
Based on the worked example above, ACI 211.1 gives the lowest cement content (369 kg/m³) for M30-equivalent concrete, primarily because its cylinder-basis strength formulation results in a slightly higher w/c ratio (0.54) compared to IS 10262 (0.49) for the equivalent cube grade. IS 10262 gives 380 kg/m³ and DOE gives 390 kg/m³. However, these differences (±21 kg/m³) reduce significantly once actual standard deviation data is substituted for assumed values in IS 10262 or ACI 318. Actual plant data reduces IS 10262 TMS margin from 8.25 MPa (assumed S=5.0) to as low as 4.1 MPa (for actual σ = 2.5) — cutting cement by 30–40 kg/m³.
Q2: Is it acceptable to use ACI 211.1 for an Indian project when IS 10262 is the governing standard?
No. IS 456:2000 Cl. 9.1 requires that concrete mix design for M30 and above shall be carried out as per IS 10262. Using ACI 211.1 alone is not compliant with Indian structural codes. On internationally funded projects (World Bank, ADB) where ACI specifications are contractually required, both IS 10262 and ACI 211.1 reports may need to be submitted — demonstrating compliance with both systems. In practice, the governing approval authority (PWD, NHAI, structural engineer of record) will specify which standard is controlling.
Q3: What is the main advantage of the DOE method over IS 10262?
The DOE method’s principal advantage is its explicit treatment of fine aggregate grading via the % passing 600 µm sieve (C-value). This parameter more sensitively captures the impact of sand grading on water demand and paste requirement than IS 10262’s four-zone classification (Zone I–IV). For projects with unusual or variable sand gradings (outside standard IS 383 zones), the DOE approach can produce more accurately proportioned mixes. However, the graphical chart basis and the requirement for C-value data make DOE less suitable for routine Indian practice where IS 383 zone classification is standard.
Q4: How do I convert between IS cube strength and ACI cylinder strength for the same nominal concrete?
The standard approximate conversion for normal-weight concrete is: fck,cube ≈ 1.25 × f’c,cylinder (or f’c ≈ 0.80 × fck). Therefore: M30 cube (fck = 30 MPa) ≈ f’c = 24 MPa cylinder (ACI C24). However, this ratio varies with strength level — at higher strengths (M60+), the ratio approaches 1.15–1.20 rather than 1.25. For structural calculations, always use the specimen type specified by the governing standard — do not convert between cube and cylinder results for structural acceptance criteria without explicit guidance from the structural engineer of record.
Q5: Does BS EN 206 require a specific mix design calculation procedure?
No — unlike IS 10262 and ACI 211.1, BS EN 206 is a specification standard, not a proportioning procedure standard. It defines what properties the concrete must achieve and the minimum requirements for each exposure class, but leaves the mix proportioning method to the concrete producer’s Factory Production Control (FPC) system. Producers typically use their own proven mix design procedure (which may be based on ACI 211.1, DOE, or their own empirical database) and must demonstrate conformity through initial type testing and ongoing production control per EN 206 Cl. 8 and 9. The specifier never needs to approve the producer’s proportioning method — only the resulting concrete’s conformity with specified properties.
Q6: Can I use IS 10262:2009 (old version) instead of IS 10262:2019?
Most Indian authorities accept IS 10262:2009 where it was the applicable standard at the time of mix design, but IS 10262:2019 is the current standard and must be used for new mix designs from 2019 onwards. The differences are not merely editorial — the 2019 edition has updated water content tables, revised standard deviations, and formally includes M-Sand and SCM guidance that was absent in 2009. Submitting a 2009-basis design for new construction will typically be queried or rejected by checking engineers on significant projects. Use 2019 for all new designs.
📝 Key Standards & External References — Mix Design Methods 2026
- IS 10262:2019: Concrete Mix Proportioning — Guidelines (primary Indian standard)
- IS 456:2000: Plain & Reinforced Concrete — Code of Practice (durability, min cement, max w/c)
- ACI 211.1-91 (reaffirmed 2022): Standard Practice for Selecting Proportions for Normal Concrete
- ACI 318-19: Building Code Requirements (f’cr formula, w/cm limits by exposure)
- BS EN 206:2013+A2:2021: Concrete — Specification, Performance, Production and Conformity
- BS 8500:2015+A2:2019: Concrete — Complementary British Standard to EN 206
- IRC:44-2017: Guidelines for Cement Concrete Mix Design for Pavements
- IRC:15-2017: Standard Specifications and Code of Practice for Construction of Concrete Roads
- AS 1379:2007: Specification and Supply of Concrete (Australian standard)
- ACI 363R-10: Report on High-Strength Concrete (HSC mix design guidance)
- IS 16714:2018: Recycled Aggregate for Use in Concrete — Specification
- BRE Concrete Practice (1997): Design of Normal Concrete Mixes — DOE Method (Building Research Establishment)