About this code
Step-by-step procedure for designing concrete mixes for normal, high-strength, and self-compacting concrete. Replaces the 2009 edition with updated tables for blended cements and admixtures.
Key sections
- 01Scope and references
- 02Data for mix proportioning
- 03Procedure for normal concrete
- 04High-strength concrete
- 05Self-compacting concrete
- 06Annex A: Worked examples
Critical clauses
f_target = fck + 1.65 × s, where s is standard deviation per Table 1.
In practiceM30: target = 30 + 1.65×5 = 38.25 MPa.
Base water 186 kg/m3 (20mm aggregate, 50mm slump), adjusted for slump and aggregate.
In practiceAdd 3% water per 25mm slump increase; reduce with admixture.
Cement = water / (w/c ratio); check against IS 456 minimum.
In practiceAlways take the higher of mix design value and durability minimum.
Volume of CA per Table 5 based on FA zone and w/c.
In practiceAdjust ±0.01 volume CA per 0.05 change in w/c from 0.5.
For M60+, use silica fume, low w/b, and superplasticizer.
In practicew/b 0.30-0.35; silica fume 7-10% by mass cementitious.
Practical implications
Specify target strength and exposure; let RMC do mix design.
Maintain trial mix records; recalibrate every quarter.
Verify fresh concrete slump matches design intent.
FAQs
Yes — clause 6 covers high-strength concrete up to M100.
No — nominal mix is per IS 456 Table 9, only up to M20.
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