IS 10262:2019 — Concrete Mix Design Quick Reference
Bureau of Indian Standards | IS 10262:2019 | Bastukar.in Civil Engineering Reference
1. Target Mean Strength (f'ck)
As per IS 10262:2019 Clause 5.2: f'ck = fck + 1.65 × s
f'ck = fck + 1.65 × s (where s = standard deviation from IS 456:2000 Table 8)
Grade
fck (MPa)
Std Dev s (MPa)
f'ck = fck+1.65s (MPa)
Category
M10
10
3.5
15.78
Ordinary
M15
15
3.5
20.78
Ordinary
M20
20
4.0
26.60
Standard
M25
25
4.0
31.60
Standard
M30
30
5.0
38.25
Standard
M35
35
5.0
43.25
Standard
M40
40
5.0
48.25
High
M45
45
5.0
53.25
High
M50
50
5.0
58.25
High
M55
55
5.0
63.25
High
M60
60
5.0
68.25
High
2. Water Content — IS 10262:2019 Table 2
Maximum water content (litres) per cubic metre of concrete for nominal maximum size of aggregate:
Nominal Max Agg. Size (mm)
Slump 25–50 mm
Slump 51–100 mm
Slump 101–150 mm
10
208
219
230
12.5
200
211
222
20
186
197
208
25
181
192
203
40
175
186
197
Note: Values are for angular crushed coarse aggregate and medium sand (Zone II). For sub-angular aggregates reduce water by 10 litres/m³; for gravel reduce by 20 litres/m³.
3. Water-Cement Ratio Limits — IS 456:2000 Table 5
Exposure Condition
Plain Concrete Max W/C
Reinforced Concrete Max W/C
Min Cement (kg/m³) PCC
Min Cement (kg/m³) RCC
Mild
0.60
0.55
220
300
Moderate
0.60
0.50
240
300
Severe
0.50
0.45
250
320
Very Severe
0.45
0.40
260
340
Extreme
0.40
0.35
280
360
4. Coarse Aggregate Fraction — IS 10262:2019 Table 3
Volume of coarse aggregate per unit volume of total aggregate for different zones of fine aggregate:
Nominal Max Agg. Size (mm)
FA Zone I (Coarser)
FA Zone II
FA Zone III
FA Zone IV (Finer)
10
0.50
0.48
0.46
0.44
12.5
0.59
0.57
0.55
0.53
20
0.66
0.64
0.62
0.60
25
0.71
0.69
0.67
0.65
40
0.75
0.73
0.71
0.69
Adjustment: For each 0.05 increase or decrease in w/c ratio (from 0.50), increase or decrease the CA fraction by 0.01.
5. Specific Gravity of Materials (Typical Values)
Material
Specific Gravity
Remarks
OPC Cement (IS 269)
3.10 – 3.15
Use 3.15 if not tested
Fine Aggregate (natural sand)
2.60 – 2.65
Use 2.65 if not tested
Coarse Aggregate (granite)
2.70 – 2.75
Use 2.74 if not tested
Coarse Aggregate (limestone)
2.60 – 2.65
—
Water
1.00
—
Fly Ash (IS 3812)
2.0 – 2.2
Blended cement/admixture
GGBS
2.8 – 2.9
Ground Granulated Blast Furnace Slag
6. Mix Design Steps Summary (IS 10262:2019)
Step 1 — Target Strength: Calculate f'ck = fck + 1.65s. Select standard deviation from IS 456 Table 8 based on grade.
Step 2 — W/C Ratio: Select maximum permissible w/c ratio from IS 456:2000 Table 5 for the given exposure condition. Also check w/c ratio from Table 6 of IS 456 for durability.
Step 3 — Water Content: Select water content from IS 10262 Table 2 based on aggregate size and required slump. Adjust for admixtures if used (typically reduce by 20–30% for superplasticizers).
Step 4 — Cement Content: C = W / (w/c ratio). Check against minimum cement content from IS 456 Table 5. Use the higher value.
Step 5 — CA Fraction: From IS 10262 Table 3, find volume fraction of CA based on aggregate size and FA zone. Adjust for w/c ratio.
Step 6 — Aggregates by Absolute Volume: Volume of all ingredients (cement + water + FA + CA + air) = 1 m³. Solve for FA and CA masses using specific gravities.
Step 7 — Trial Mix: Prepare trial mix and check workability (slump/Vee-Bee), density, and strength at 7 days and 28 days.
Step 8 — Adjustments: Adjust water, cement, aggregates as required based on trial mix results. Final mix proportions after adjustment become the design mix.
7. Worked Example — M25 Concrete Mix Design
Given: Grade M25, Moderate exposure, 20mm CA, Zone II FA, Slump 75mm, No admixture. G = 2.74 (CA), 2.65 (FA), 3.15 (Cement).
8. Acceptance Criteria for Concrete — IS 456:2000 Cl. 16
Test
Acceptance Criterion
Individual 28-day cube strength
Not less than fck – 3 MPa (for M25: not less than 22 MPa)
Average of 4 consecutive non-overlapping samples
Not less than fck + 0.825 × established standard deviation, or fck + 3 MPa, whichever is greater
Slump Test (workability)
Within ±25 mm of specified slump, or within ±25% for slump > 50mm
Minimum samples
1 sample per 50 m³ (min.) or 1 per day of casting
Cubes per sample
Minimum 3 cubes (150mm × 150mm × 150mm)
Important: IS 10262:2019 replaced IS 10262:2009. Key change: the water content table now directly accounts for slump ranges and a modified absolute volume approach is used.