Engineering Materials·MCQ explained

Which of the following is CORRECT for the workability of the concrete having the compaction factor of 0.92?

Try it first: pick an option, then read the explanation.

Correct answer: C. Medium

Detailed Explanation: CF 0.92 = Medium Workability

Why C (Medium) is correct: Per IS 456 classification, CF = 0.85–0.92 corresponds to medium workability. CF = 0.92 is at the upper boundary of medium. High workability begins at CF > 0.92. Note: some references treat 0.92 exactly as the transition point — in exam context, CF = 0.92 = medium (not yet high). CF > 0.92 (e.g., 0.95) = high.

IS Compaction Factor Classification

Compaction FactorWorkabilityEquiv. Slump
<0.75Very low0–25 mm
0.75–0.85Low25–75 mm
0.85–0.92 (CF=0.92)Medium50–100 mm
>0.92High100–150 mm
  • CF 0.92 = upper boundary of medium workability.
  • CF 0.95 = high workability (Q47 and Q66).