Guidelines for concrete mix design proportioning

IS 10262: Scope & Key Specifications

• Scope (Clause 1.3):
  IS 10262 governs concrete mix proportioning and incorporates all applicable requirements of IS 456:2000 (Plain and Reinforced Concrete). It references related standards for materials and testing.

• Referenced Standards:

  IS No.	Title
  383:1970	Coarse & fine aggregates specification
  456:2000	Code of practice for concrete
  2386(Part 3):1963	Aggregate testing methods
  3812(Part 1):2003	Pulverized fuel ash specification
  8112:1989	43 grade OPC specification
  9103:1999	Admixtures for concrete

• Target Strength Formula (Clause 1.65):
  [ f'{ck} = f{ck} + 1.65 \times s ]
  Where:

  • ( f'_{ck} ) = Target mean compressive strength (N/mm²)
  • ( f_{ck} ) = Characteristic compressive strength (N/mm²)
  • ( s ) = Standard deviation (N/mm²) from Table 1

• Assumed Standard Deviation (Table 1):

  Grade	Std. Deviation (N/mm²)
  M10	3.5
  M20	4.0
  M40	5.0

• Water-Cement Ratio:
  From IS 456 Table 5, max water-cement ratio depends on exposure. Example: For severe exposure, max = 0.45.

• Mix Proportioning Guidelines:

  • Adjust volume of coarse aggregate based on water-cement ratio (±0.01 per ±0.05 change).
  • For pumpable concrete, reduce coarse aggregate volume by 10%.
  • Use trial mixes and adjust water content, especially with admixtures.

Summary Flowchart of Mix Proportioning (Simplified)

flowchart TD
    A[Start: Define Grade & Exposure] --> B[Select Characteristic Strength

IS 10262 References Summary

IS 10262 relies heavily on related standards for concrete mix design and materials:

Key Notes:

• IS 456 provisions are integral to IS 10262.
• Standard deviations for concrete strength (for mix design) are given in Table 1 of IS 10262:

(Increase by 1 N/mm² if site control is poor)

Additional:

• Mix proportioning uses material data like moisture content, sieve analysis per IS 383.
• Mix design methodology is influenced by ACI 211.1 for normal and mass concrete.

flowchart LR
    A[IS 10262 Mix Design] --> B[IS 383 Aggregates]
    A --> C[IS 456 Concrete Code]
    A --> D[IS 2386 Aggregate Tests]
    A --> E[IS 3812 Pozzolana]
    A --> F[IS 8112 Cement]
    A --> G[IS 9103 Admixtures]

IS 10262: Data for Mix Proportioning - Key Formulas & Tables

1. Target Strength for Mix Proportioning

[ f'{ck} = f{ck} + 1.65 \times s ]

• (f'_{ck}) = target mean compressive strength (N/mm²)
• (f_{ck}) = characteristic compressive strength (N/mm²)
• (s) = standard deviation (N/mm²), typically 5 N/mm² (Table A-3)

Example:
For M40 concrete:
[ f'_{ck} = 40 + 1.65 \times 5 = 48.25 , \text{N/mm}^2 ]

2. Water-Cement Ratio

• From IS 456 Table 5, max water-cement ratio for M40 = 0.45
• Adopted value (experience): 0.40 (< 0.45, acceptable)

3. Water Content (for 20 mm aggregate)

• Max water content for 25-50 mm slump = 186 liters/m³ (Table 2)
• Adjusted for 100 mm slump and superplasticizer (29% reduction):
  [ Water = 197 \times 0.71 = 140 , \text{liters/m}^3 ]

4. Cement Content

[ \text{Cement} = \frac{\text{Water content}}{\text{Water-cement ratio}} = \frac{140}{0.40} = 350 , \text{kg/m}^3 ]

• Min cement content for severe exposure (IS 456 Table 5) = 320 kg/m³ → OK

5. Aggregate Proportions (Volume basis)

• From Table 3, coarse aggregate volume for 20 mm size & w/c=0.50 = 0.60
• Adjust for w/c=0.40 (-0.10 difference): increase coarse aggregate volume by 0.02 → 0.62
• For pumpable concrete reduce by 10% → 0.62 × 0.9 = 0.56 (coarse aggregate volume)
• Fine aggregate volume = 1 - 0.

IS 10262: Selection of Mix Proportions - Key Formulas & Tables

1. Target Strength for Mix Proportioning (Clause 1.65)

[ f'{ck} = f{ck} + 1.65 \times s ]

• (f'_{ck}): Target mean compressive strength at 28 days (N/mm²)
• (f_{ck}): Characteristic compressive strength (N/mm²)
• (s): Standard deviation (N/mm²), typically 5 N/mm²

Example:

For M40 concrete,

[ f'_{ck} = 40 + 1.65 \times 5 = 48.25 \text{ N/mm}^2 ]

2. Water-Cement Ratio (From IS 456 Table 5)

• Maximum water-cement ratio for M40 (severe exposure): 0.45
• Adopted water-cement ratio (based on experience): 0.40 (≤ 0.45, acceptable)

3. Water Content (From Table 2, IS 10262)

• Max water content for 20 mm aggregate & 25-50 mm slump: 186 liters
• Adjusted for 100 mm slump (approximate):
  [ 186 + 6% \times 186 = 197 \text{ liters} ]
• With superplasticizer (29% reduction):
  [ 197 \times 0.71 = 140 \text{ liters} ]

4. Cement Content Calculation

[ \text{Cement content} = \frac{\text{Water content}}{\text{Water-cement ratio}} = \frac{140}{0.40} = 350 \text{ kg/m}^3 ]

• Minimum cement content (severe exposure) from IS 456: 320 kg/m³
• Adopted cement content: 350 kg/m³ (OK)

5. Coarse and Fine Aggregate Volume Proportion (From Table 3)

• For 20 mm aggregate and water-cement ratio 0.50, volume of coarse aggregate = 0.60
• Adjust for w/c = 0.40: increase by 0.02 → 0.62

IS 10262 Trial Mix & Adjustments - Key Formulas and Tables

1. Target Strength Calculation

[ f'{ck} = f{ck} + 1.65 \times s ]

• (f'_{ck}) = target average compressive strength at 28 days
• (f_{ck}) = characteristic compressive strength
• (s) = standard deviation (typically 5 N/mm² for normal concrete)

Example: For M40,
[ f'_{ck} = 40 + 1.65 \times 5 = 48.25 \text{ N/mm}^2 ]

2. Water-Cement Ratio Selection

• From IS 456 Table 5, max w/c ratio depends on exposure (e.g., max 0.45 for severe exposure)
• Adopt w/c ratio ≤ max limit (e.g., 0.40 for M40)

3. Water Content Adjustment

• Base water content from IS 10262 Table 2 (for 20 mm agg. and slump 25-50 mm): e.g., 186 L/m³
• Adjust for slump:
  [ W = W_{base} + \frac{\Delta slump}{6} \times W_{base} ]
• Reduce water content if using superplasticizer (up to 20-30%)

4. Cement Content Calculation

[ \text{Cement} = \frac{\text{Water content}}{\text{Water-cement ratio}} ]

• Check minimum cement content per IS 456 Table 5 (e.g., 320 kg/m³ for severe exposure)

5. Aggregate Proportioning

• Volume of coarse aggregate from IS 10262 Table 3 (adjusted for w/c ratio):
  [ V_{coarse} = V_{base} \pm 0.01 \text{ for every } \pm 0.05 \text{ change in w/c} ]
• Fine aggregate volume = 1 - (V_{coarse})
• For pumpable concrete, reduce coarse aggregate volume by 10%

6. Mix Calculations (per m³ concrete)

[ \text{Volume of cement}

IS 10262 Illustrative Examples: Key Formulas, Tables & Specs

1. Mix Calculation Formula (Clause 2.74 Example)

[ \text{Fine Aggregate (kg)} = 0.743 \times 0.44 \times 2.74 \times 1000 = 896 \text{ kg/m}^3 ]

2. Trial Mix Proportions (Example for M40 grade)

Note: Adjust water content for moisture in aggregates as per IS 2386.

3. Volume Calculation for Aggregates (Clause 4.6)

[ V = 1 - \left(\frac{W_c}{SG_c \times 1000} + \frac{W_w}{SG_w \times 1000} + \frac{W_a}{SG_a \times 1000}\right) ]

• (W_c, W_w, W_a) = mass of cementitious material, water, admixture (kg)
• (SG_c, SG_w, SG_a) = specific gravities

Split volume (V) into fine and coarse aggregate fractions based on mix design.

4. Trial Mix Adjustments

• Measure slump and workability.
• Adjust water/admixture to achieve target slump.
• Maintain free water-cement ratio.
• Prepare multiple trial mixes varying water-cement ratio ±10%.

5. Annex B: Fly Ash Mix Proportioning

• Fly ash partially replaces OPC.
• Follow similar steps with adjusted cementitious content.
• Use IS 3812 for fly ash specs.

References for Material Properties & Tests:

• IS 2386 (Part 3): Aggregate moisture & absorption
• IS 8112: OPC 43 grade cement
• IS 3812 (Part 1): Fly ash
• IS 9103: Ad

IS 10262: Illustrative Example on Concrete Mix Proportioning (M40 Grade)

Key Steps & Formulas:

1. Target Strength:

[ f'{ck} = f{ck} + 1.65 \times s ]

• (f_{ck}) = characteristic strength (40 N/mm²)
• (s) = standard deviation (5 N/mm²)
• (\Rightarrow f'_{ck} = 40 + 1.65 \times 5 = 48.25 , \text{N/mm}^2)

2. Water-Cement Ratio:

• From IS 456 Table 5, max water-cement ratio = 0.45
• Adopted = 0.40 (based on experience and durability)

3. Water Content:

• Base water content for 20 mm aggregate & 25-50 mm slump = 186 L
• Adjusted for 100 mm slump and superplasticizer (29% reduction):

[ 197 \times 0.71 = 140 , \text{L} ]

4. Cement Content:

[ \text{Cement} = \frac{\text{Water Content}}{\text{Water-Cement Ratio}} = \frac{140}{0.40} = 350 , \text{kg/m}^3 ]

• Minimum cement content for severe exposure = 320 kg/m³ → OK

5. Aggregate Volume Proportions:

• Coarse aggregate volume (for 0.40 w/c): 0.62 (corrected from 0.60)
• For pumpable concrete, reduce by 10% → 0.56
• Fine aggregate volume = 1 - 0.56 = 0.44

6. Aggregate Mass Calculation:

[ \text{Mass} = \text{Volume} \times \text{Specific Gravity} \times 1000 ]

• Fine aggregate = 0.44 × 2.74 × 1000 = 1205 kg (example)
• Coarse aggregate = 0.56 × 2.74 × 1000 = 1534 kg (example)

Trial Mix Proportions (Example from Table A-9):

| Material | Quantity (kg/m³) |

IS 10262: Illustrative Example Using Fly Ash (M40 Concrete Mix)

Key Data & Mix Proportions (Trial 1)

Important Formulas & Calculations

• Total Cementitious Material Content:

  [ \text{Cementitious} = 350 \times 1.10 = 385 \text{ kg/m}^3 ]

• Fly Ash Content (30% replacement):

  [ \text{Fly Ash} = 385 \times 0.30 = 115 \text{ kg/m}^3 ]

• Cement Content:

  [ \text{Cement} = 385 - 115 = 270 \text{ kg/m}^3 ]

• Water-Cement Ratio:

  [ w/c = \frac{140}{385} = 0.364 ]

• Coarse Aggregate Volume Adjustment:

  Base volume from Table 3 = 0.60 (for w/c=0.50)

  Adjusted for w/c=0.40:

  [ 0.60 + 0.02 = 0.62 ]

  For pumpable concrete, reduce by 10%:

  [ 0.62 \times 0.9 = 0.56 ]

• Fine Aggregate Volume:

  [ 1 - 0.56 = 0.44 ]

• Mass of Aggregates Calculation:

  [ \text{Mass} = \text{Volume} \times \text{Specific Gravity} \times 1000 ]

Notes

• Aggregates must be in saturated surface dry (SSD) condition; adjust water content for moisture.
• Slump and admixture dosage to be adjusted

IS 10262 - Committee Composition & Key Specifications

Committee Composition (Annex C, Foreword)
The Cement and Concrete Sectional Committee CED 2 includes representatives from:

• Cement manufacturers (e.g., ACC Ltd, Ultra Tech Cement, Gujarat Ambuja)
• Government bodies (Atomic Energy Regulatory Board, Central Water Commission, Ministry of Road Transport & Highways)
• Research institutes (CSIR-Central Building Research Institute, Structural Engineering Research Centre)
• Academia (IIT Roorkee, R.V. College of Engineering)
• Industry bodies (Indian Concrete Institute, Indian Roads Congress)
• Others: Military Engineer Services, Public Works Departments, Fly Ash Utilization Programme

Key Notes:

• The committee ensures the standard reflects practical and research inputs.
• The composition is multidisciplinary covering all major stakeholders in concrete technology.

Important Formulas & Tables from IS 10262 for Mix Design

Table 1: Assumed Standard Deviation (N/mm²)