M15 concrete is used for:
Correct Answer: B. Foundation
📚 Detailed Explanation: Applications of M15 Concrete
Why B (Foundation) is correct:
A — Dams: Gravity dams use mass concrete (M10 equivalent or lower, with very large aggregates). M15 is not specifically used for dams.
B — Foundation: M15 (1:2:4) is ideal for plain concrete foundations (PCC underneath RCC footings, blinding layers, mass foundations). Correct answer.
C — RCC: IS 456 mandates minimum M20 for all reinforced concrete structural members. M15 is below the minimum for RCC.
D — Mass concreting: While M15 could be used for some mass concrete, M10 is typically used for bulk/mass fills.
A — Dams: Gravity dams use mass concrete (M10 equivalent or lower, with very large aggregates). M15 is not specifically used for dams.
B — Foundation: M15 (1:2:4) is ideal for plain concrete foundations (PCC underneath RCC footings, blinding layers, mass foundations). Correct answer.
C — RCC: IS 456 mandates minimum M20 for all reinforced concrete structural members. M15 is below the minimum for RCC.
D — Mass concreting: While M15 could be used for some mass concrete, M10 is typically used for bulk/mass fills.
Grade-to-Application Guide
| Grade | Primary Application |
|---|---|
| M10 | Blinding, levelling course, mass concrete fills |
| M15 | Plain concrete foundations, PCC, non-structural |
| M20 | General RCC (minimum for reinforced members) |
| M25–M30 | High-load columns, pre-stressed elements, exposure zones |
- M15 = foundation and plain concrete works.
- M15 is NOT permitted for reinforced concrete members (minimum M20 per IS 456).