The size of the aggregate accepted as suitable for R.C.C. construction

1.	The size of the aggregate accepted as suitable for R.C.C. construction work is about:- 1. 5 mm to 20 mm2. 3 mm to 5 mm3. 1.0 mm to 3 mm4. 0.5 mm to 1.0 mm
Answer» Correct Answer - Option 1 : 5 mm to 20 mm Concept: As per IS 456:2000 maximum size of aggregate for concrete should be confined to: (a)As per Cl 5.3.3 For most works, 20 mm aggregate is suitable When there is no restriction to the flow of concrete, 40 mm or larger aggregate is preferred. In thin sections, small cover, or closely-spaced reinforcements, considerations should be given to use 10 mm aggregate. (b)As per Cl 5.3.3.1 For heavily reinforced concrete members like ribs of main members, the nominal maximum size of aggregate should be usually restricted to 5 mm less than the minimum clear distance between the main bars 5 mm less than the minimum cover – whichever is smaller (c) It should not be more than one-fourth of the minimum thickness of the member. So, The size of the aggregate accepted as suitable for R.C.C. construction work is about 5mm to 20mm. IS 383 (1970): Specification for coarse and fine aggregates from natural sources for concrete.

The size of the aggregate accepted as suitable for R.C.C. construction work is about:- 1. 5 mm to 20 mm2. 3 mm to 5 mm3. 1.0 mm to 3 mm4. 0.5 mm to 1.0 mm

Answer» Correct Answer - Option 1 : 5 mm to 20 mm

Concept:

As per IS 456:2000 maximum size of aggregate for concrete should be confined to:

(a)As per Cl 5.3.3

For most works, 20 mm aggregate is suitable
When there is no restriction to the flow of concrete, 40 mm or larger aggregate is preferred.
In thin sections, small cover, or closely-spaced reinforcements, considerations should be given to use 10 mm aggregate.

(b)As per Cl 5.3.3.1

For heavily reinforced concrete members like ribs of main members, the nominal maximum size of aggregate should be usually restricted to
- 5 mm less than the minimum clear distance between the main bars
- 5 mm less than the minimum cover – whichever is smaller

(c) It should not be more than one-fourth of the minimum thickness of the member.

So, The size of the aggregate accepted as suitable for R.C.C. construction work is about 5mm to 20mm.

IS 383 (1970): Specification for coarse and fine aggregates from natural sources for concrete.