I am planning to mold 6" solid blocks (not hollow) for a duplex I'm about to start working on. The building will have two floors (a ground floor and a second level above the ground floor). In Nigeria, this will be called a one-story building; in the US, it will be a two-story building.

I have talked with various block molders who assured me that they've been molding blocks for years. But I'm not naïve when it comes to the level of quackery in Nigeria. For every stage of this project, I want to go in with reliable information. Help me out, guys.

The cement I have bought are Dangote 50 kg bags. My architect and the molders say for my blocks (6" solid blocks) to be strong, I should mold 30 blocks from each bag of cement. Here is my question: In order to obtain thirty 6" solid blocks from a 50 kg bag of cement (Dangote cement), what should be the ratio of cement to sand and water? How many head-pans of cement should be mixed with how many head-pans of sand? How much water should be in the mix? In other words, how many parts of cement should be mixed with how many parts of sand and water?

If you couldn't believe or at least come to a consensus with the data provided by the several block moulders you contacted, I doubt you'd believe what you get here also.

However, I'll try. A typical 6" solid block has dimensions of 150mm x 450mm x 225mm.
The volume is, 0.0152 cumec.

30 blocks will be 0.0152 x 30 = ~0.46 cumec.

So, you will need 0.035.cumec of cement for ~0.46 cumec of blocks. (50kg bag = 0.035 cumec)

Subtract cement from the block your have 0.421 cumec of sand.

Cement : Sand = 0.035 : 0.421 = 1 : 12

Your bag of cement is equivalent to 2 standard construction headpans. However, what ever the measuring container you wish to use make sure that for every one measure of cement that you add 12 measures of sand.

Another important point to note is the water-cement ratio. But that's a topic for some other time. Cheers!!



P.S.
Cumec = Cubic meters (m3)
I'm a civil engineer (COREN)
07033544353

Analyst01:
A typical 6" solid block has dimensions of 150mm x 450mm x 225mm.
The volume is, 0.0152 cumec.

30 blocks will be 0.0152 x 30 = ~0.46 cumec.

So, you will need 0.035.cumec of cement for ~0.46 cumec of blocks. (50kg bag = 0.035 cumec)

Subtract cement from the block your have 0.421 cumec of sand.

Cement : Sand = 0.035 : 0.421 = 1 : 12

Your bag of cement is equivalent to 2 standard construction headpans. However, what ever the measuring container you wish to use make sure that for every one measure of cement that you add 12 measures of sand.

Another important point to note is the water-cement ratio. But that's a topic for some other time. Cheers!!



P.S.
Cumec = Cubic meters (m3)
I'm a civil engineer (COREN)
07033544353

Thanks. This was helpful.

I've noticed that the molders could "eyeball" the ratio of cement to sand, but they could not give me this sort of answer. They used their shovels and were able to get between 29 and 31 block from each bag of cement. But I wanted an answer that's "mathematical" in order to have a standard "recipe" for making 30 solid 6" blocks out of a 50 kg bag of cement. That way, I can ensure consistency in the strength of the blocks regardless of the molder.

Again, thanks for the answer.

Kpekus:


Thanks. This was helpful.

I've noticed that the molders could "eyeball" the ratio of cement to sand, but they could not give me this sort of answer. They used their shovels and were able to get between 29 and 31 block from each bag of cement. But I wanted an answer that's "mathematical" in order to have a standard "recipe" for making 30 solid 6" blocks out of a 50 kg bag of cement. That way, I can ensure consistency in the strength of the blocks regardless of the molder.

Again, thanks for the answer.

You're welcome.

Analyst01:


You're welcome.

Good job!

[quote author=Analyst01 post=94253434]If you couldn't believe or at least come to a consensus with the data provided by the several block moulders you contacted, I doubt you'd believe what you get here also.

However, I'll try. A typical 6" solid block has dimensions of 150mm x 450mm x 225mm.
The volume is, 0.0152 cumec.

30 blocks will be 0.0152 x 30 = ~0.46 cumec.

So, you will need 0.035.cumec of cement for ~0.46 cumec of blocks. (50kg bag = 0.035 cumec)

Subtract cement from the block your have 0.421 cumec of sand.

Cement : Sand = 0.035 : 0.421 = 1 : 12

Your bag of cement is equivalent to 2 standard construction headpans. However, what ever the measuring container you wish to use make sure that for every one measure of cement that you add 12 measures of sand.

Another important point to note is the water-cement ratio. But that's a topic for some other time. Cheers!!



P.S.
Cumec = Cubic meters (m3)
I'm a civil engineer (COREN)
07033544353



There is an error in your estimation. You didn't remove the volume of void in the block.

For you to have 30 numbers of 6 inches blocks from 1 bag, your ratio must be 1:6