Concrete Mix Design Flowchart

As per IS 10262:2019 and IS 456:2000

graph TD A["""Start Specify Required Grade of Concrete (e.g., M25)"""] --> B["""Determine Characteristic Compressive Strength fck in MPa"""] B --> C["""Select Standard Deviation s from IS 10262 Table 2"""] C --> D["""Calculate Target Mean Compressive Strength"""] D --> E["""ft = fck + 1.65 × s (IS 10262 Clause 6.1)"""] E --> F["""Select Maximum Water-Cement Ratio from IS 456 Table 5"""] F --> G["""Select Water Content from IS 10262 Table 4"""] G --> H["""Select Maximum Nominal Size of Aggregate (10, 20, 40 mm)"""] H --> I["""Determine Volume of Coarse Aggregate per Unit Volume from IS 10262 Table 5"""] I --> J["""Calculate Cement Content = Water ÷ W/C Ratio"""] J --> K["""Check Minimum Cement Content as per IS 456 Table 5"""] K --> L{"""Cement Content ≥ Minimum Required?"""} L -->|Yes| M["""Estimate Entrapped Air Content from IS 10262 Table 6"""] L -->|No| N["""Revise W/C Ratio or Increase Water Content and Recalculate"""] N --> F M --> O["""Calculate Absolute Volume of Cement (Cement / Sp. Gr.)"""] O --> P["""Calculate Absolute Volume of Water (Water / 1.0)"""] P --> Q["""Calculate Absolute Volume of Coarse Aggregate"""] Q --> R["""Calculate Absolute Volume of Fine Aggregate (Balance Volume)"""] R --> S["""Determine Final Proportions of Fine and Coarse Aggregates"""] S --> T["""Adjust Mix for Aggregate Moisture and Absorption (Surface & Free)"""] T --> U["""Prepare Trial Mix 1 in Laboratory"""] U --> V["""Perform Workability Test: Slump or Compaction Factor (IS 1199)"""] V --> W{"""Workability Within Specified Range?"""} W -->|No| X["""Adjust Water or Use Admixtures and Repeat Trial Mix"""] X --> U W -->|Yes| Y["""Cast 150 mm Cube Specimens (3 Nos. per Mix) as per IS 516"""] Y --> Z["""Cure Cubes in Water for 28 Days (IS 516)"""] Z --> AA["""Conduct 28-Day Compressive Strength Test on Cubes"""] AA --> AB{"""Average Strength ≥ Target Mean Strength ft?"""} AB -->|Yes| AC["""Finalize Mix Proportions for Site Use"""] AB -->|No| AD["""Revise W/C Ratio or Cement Content and Repeat from Step F"""] AD --> F AC --> AE["""End Approved Concrete Mix Design Ready for Use"""]

Code References

• IS 10262:2019 – Concrete Mix Proportioning – Guidelines
• Table 2: Standard deviation based on grade
• Table 4: Water content for slump and aggregate size
• Table 5: Coarse aggregate volume fraction
• Table 6: Entrapped air percentage
• Clause 6: Step-by-step mix design procedure
• IS 456:2000 – Plain and Reinforced Concrete
• Table 5: Durability requirements (W/C, min cement)
• Clause 8.2.4.1: Target strength formula
• IS 1199: Methods of sampling and workability
• IS 516: Cube testing and curing

Note: This flowchart uses the absolute volume method (IS 10262:2019). Multiple trial mixes and field adjustments are mandatory before final approval.

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