Correct Answer - Option 1 : 1 : 2 : 4
Concept:
According to IS 456-2000:
This code has designated the concrete mixes into a number of grades as M10, M15, M20, M25, M30, M35, and M40. In this designation.
The letter M refers to the mix and the number to the specified 28-day cube strength of mix in N/mm2.
The mixes of grades with their ratios are as follows:
|
Strength
|
Nominal
Mix
Design
|
Uses of Mix |
| M 5 |
1:5:10 |
For PCC work such as bedding for footing, etc. |
| M 7.5 |
1:4:8 |
|
M10
|
1:3:6
|
| M15 |
1:2:4 |
For heavy loaded RCC work such as slab, beams, arches, columns, footings, etc. |
|
M20
|
1:1.5:3
|
|
M25
|
1:1:2
|
For heavy loaded RCC work such as foundations, footing columns, beams, slabs, etc. |
|
M 30
|
Design Mix |
| M 35 |
Design Mix |
| M 40 |
Design Mix |
For pre-stressed concrete work |
| M 45 |
Design Mix |
| M 50 |
Design Mix |
| M 55 |
Design Mix |
|
M 60
and above
|
Design Mix |
For high compressive strength concrete work
|
Hence, heavy loaded R.C.C columns and R.C.C arches of long spans use concrete the ratio is taken as 1:2:4 (cement: sand: aggregate).
