(a) M15
(b) M20
(c) M10
(d) M25
Ans :- (b) M20
Explanation :-
As per IS code 456 : 2000, minimum grade of concrete used for RCC is M20, with ratio 1:1.5:3 means 1 part of cement, 1.5 part of sand and 3 part of course aggregate.
• As per IS code 456 : 1978, minimum grade of concrete used for RCC is Ml5.
Note-
• Min grade of concrete in post-tensioning concrete = M 30
• Min grade of concrete in pre-tensioning concrete = M 40
• Min grade of concrete in sea water construction = M 30
