Concrete mix query

[ash1212002]

4 bags of ballast and half a bag of concrete, out of interest what strength would this achieve?

 

[SFK]

After how many days? - it gets stronger every day it sets.

Normally a 6 to 1 or a 5 to 1 ratio (not the 8 to 1 that you are suggesting that is a very weak ratio), gives between 2500 and 4000 psi for normal concrete according to this link (noting they have a typo saying 25000 rather than 2500).
https://www.aboutcivil.org/compressive-strength-of-concrete.html

Why do you need to know? Building a bridge? Hopefully not with that 8:1 mix.
Sfk

 

[^woody^]

Quite strong.

 

[noseall]

4 bags of ballast and half a bag of concrete,

Half a bag of 'concrete'? You mean you are diluting concrete with ballast?

The correct (standard) mix is four parts ballast - two parts sharp (screed, grit) sand - one cement. And water of course.

 

[ash1212002]

Half a bag of 'concrete'? You mean you are diluting concrete with ballast?/QUOTE]

Yep that's correct the 25kg ballast bags I'm referring to mixed with half a bag of concrete

Wanted to know what strength will that achieve? i.e c20 c25 etc

 

[noseall]

Yep that's correct the 25kg ballast bags I'm referring to mixed with half a bag of concrete

Wanted to know what strength will that achieve? i.e c20 c25 etc

What strength is the concrete you are diluting?

 

[Notch7]

What strength is the concrete you are diluting?

Im assuming he means half a bag of cement.

 

[geraldthehamster]

Im assuming he means half a bag of cement.

They know that, they're just being naughty

 

[noseall]

I did ask the OP to clarify....?

 

[^woody^]

Is this mixed in a barrow, with the garden hose or controlled batching with known water content, measured slump value, and vibrated?

 

[ash1212002]

What strength is the concrete you are diluting?

Its half a bag of Quinn 25kg cement mixed with the 4 bags of ballast, water added into a mixer

 

[noseall]

Its half a bag of Quinn 25kg cement mixed with the 4 bags of ballast, water added into a mixer

Gotcha. It will provide you with a weaker than standard 6:1 mix but not by much. Why the scientific measuring for the strength of concrete? Are you building a dam?

Concrete is not cement by the way.

 

[Al@n]

If its any help that's a similar ratio my builder used for a mass concrete pad foundation