Civil Engineering - Building Construction - Discussion

If the slump is around this range it will be too much tight & not flow able specially in case of ares if more steel (Main & Extra Steel), I See that the slump start from 75 mm to 125 mm, However this mentioned slump from 50 mm to 10 mm is recommended for Gunite Concrete.

How? Explain the answer.

It should be 75mm to 125 mm.

For slabs and beams, it should be 30 to 125.
For columns 75 to 125.
For foundation, it should be 50 to 100.

Reinforced foundation, footings, and walls -> 50-100.mm.
Reinforced slabs and beams -> 30-125.mm.
Columns -> 75-125.mm.

Pavements -> 25-50.mm.
Mass concrete structure -> 25-50.
Unreinforced footings -> 25-75.
Bridge decks -> 25-75.mm.

Lightly reinforced foundations/strip footings: A low slump of 25 mm to 75 mm (1 to 3 inches) is often specified. This mix is stiffer but ensures proper compaction and strength for less complex forms.

Heavily reinforced foundations/footings: A medium slump of 50 mm to 100 mm (2 to 4 inches) is recommended to ensure the concrete can flow around the reinforcing steel and fill the formwork without segregation.

Mass concrete foundations (unreinforced or minimal steel): A slump of 25 mm to 50 mm is typically used.

Pumped concrete foundations: If the concrete is to be pumped, a higher slump of 75 mm to 125 mm or even up to 150 mm may be required to facilitate flow through the pipelines, often achieved with high-range water-reducing admixtures (superplasticisers) without adding excess water.