Civil Engineering - Concrete Technology - Discussion

M20 concrete is used having proportion 1:1.5:3.

IS 456 2000 M20 is 1 : 1.5 : 3.

1:2:4 is the correct answer.

M20 is right one.

Where cement concrete 1:2; 4 ratio is used it means 1 part cement 2 parts of fine aggregate or coarse sand and 4 parts of coarse aggregate. This ratio cement concrete has good strength and is recommended for the following type of buildings and works:-

- Used in footings of columns and raft foundation, used in beams, slabs, columns, stairs and walls of ordinary, single story and temporary buildings and used in retaining walls, pavements, floors and bedplates etc.

- Where cement concrete 1:1:5:3 ratio is used it means 1 part cement 1.5 parts of fine aggregate or coarse sand and 3 parts of coarse aggregates. This ratio cement concrete has very good strength and is recommended for the following type of buildings and works:-

- Important RCC structures, piles, arches, impermeable construction against water heads. This ratio of cement concrete is safe against earth quake.

1:1.5:3 is M20 grade of concrete. 1:2:4 is M20 Grade of Concrete & for RCC minimum M20 grade is use as per IS 456-2000.

Generally, M15(1:2:4) used.

IS 456:2000 suggests a minimum M20 for RCX so the answer should be B.

It's for m20 is correct.

The right answer is M20 grade that is 1:1.5:3.