IS 10262Cl. 4

Target mean strength for mix proportioning

Target mean strength = characteristic compressive strength + 1.65 × standard deviation. Standard deviation depends on grade (Table 1) for trial design; use site values once available.

Formulas

Target mean
f'_ck = f_ck + 1.65 × s

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Editorial paraphrase for fast lookup — the official IS 10262 text is authoritative. For exact wording, refer to the published code.