Aggregate impact value

Calculate impact fines and check sample recovery before combining duplicate determinations.

Observations and units

• Initial oven-dry sample mass (g)
• Mass passing 2.36 mm sieve (g)
• Mass retained on 2.36 mm sieve (g)

Calculation

Impact value = 100 × fines / initial mass; unrecovered mass = initial − fines − retained.

Method reference and limitations

IS 2386 (Part 4):1963, clauses 4.4.4–4.6. Standard 12.5–10 mm sample and prescribed impact procedure only. If loss exceeds 1 g, repeat that determination. Any apparent mass gain is flagged for review. Trial reporting uses one decimal place and the mean a whole percent; exact arithmetic remains available.

Calculation and reporting rules audited within the documented profile; physical test execution and specification acceptance remain the operator’s responsibility. Independent qualified review is not recorded. No certificate or compliance decision.

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