The permissible compressive strength of M-30 concrete grade (in kg/cm²) is:
Try it first: pick an option, then read the explanation.
Correct answer: D. 300
M-30 Strength in kg/cm²
Step 1. M30 → fck = 30 N/mm²
Step 2. Convert:30 N/mm² × 10.2 = 306 kg/cm² ≈ 300 kg/cm²
M-30 permissible compressive strength ≈ 300 kg/cm² — option D.
Key takeaway
M × 10 = kg/cm² (approximate). M30 → 300, M25 → 250, M20 → 200.