The minimum grade of RCC and maximum cement content as per IS 456
| The minimum grade of RCC and maximum cement content as per IS 456 : 2000 in severe exposure condition is
A. M – 25 and 320 kg/m<sup>3</sup>
B. M – 25 and 450 kg/m<sup>3</sup>
C. M – 30 and 320 kg/m<sup>3</sup>
D. M – 30 and 450 kg/m<sup>3</sup>
Please scroll down to see the correct answer and solution guide.
Right Answer is: D
SOLUTION
Concept:
As per IS 456 : 2000, Table 5;
|
Environment |
Maximum grade of RCC |
Minimum grade of PCC |
Nominal Cover |
|
1. Mid |
M – 20 |
- |
20 mm |
|
2. Moderate |
M – 25 |
M 15 |
30 mm |
|
3. Severe |
M – 30 |
M 20 |
45 mm |
|
4. Very severe |
M – 35 |
M 20 |
50 mm |
|
5. Extreme |
M - 40 |
M 25 |
75 mm |
Cement content should not exceed 450 kg/m3.
Important Point:
Severe condition arises from concrete surfaces exposed to severe rain, alternate wetting and drying or occassional freezing.