Civil Engineering - Building Materials - Discussion

Explian how come .45?

Minimum W/C ratio 0.38.
So required water= 50 x 0.38 = 19lt.

For normal consistency, minimum w/c ratio is 0.45 that's why w = 0.45 * 50 = 22.5.

But the min w/c ratio is 0.4 and max w/c is 0.8 how we can consider 0.45?

They must have to specify the w/c ratio. Please explain.

35 litres is correct for 50kg cement.

Minimum water cement ratio for workable concrete is 04.

So, we may say 0.4*50 = 20 liters. I think the answer should be 20.5.

For thin structures subjected to wetting and drying, the water-cement ratio should be 0.45.
For mass concrete structures subjected to wetting and drying, the water ratio should be 0.55.
For thin structures which remain continuously underwater, the water-cement ratio by weight should be 0.55.
For massive concrete structures which remain continuously underwater, the water-cement ratio by weight should be 0.65.

For 50 kg bag 35L of water is required. Without w/c ratio one can't find the solution.

Am I right? Please explain me.