Concrete calculators

[julianf]

When I mix concrete I sling two, not quite full, buckets of all-in aggregate into the mixer with a half bag of cement.


Anyway, I reckon this gives me a 4:1 mix.

So that side of it all works fine when I'm buying bulk bags, but, where I always stuff up is in the calculations as to how much aggregate to buy.


I *think* (but am unsure - could someone confirm?) that a small bag of aggregate is a bucket full? (I generally buy dumpy bags)



Would I be right in thinking that a standard black bucket is 10ltrs to a bit under the rim, and that the cement does not change the volume of the mix at all (as it goes between all the gaps)?

So that would mean my mixes are 20l per batch, right?

And, from that, I should be able to work out what to buy? And not end up half a bulk bag too much or too little like I normally manage!

 

[frank horton]

cant help with such small quant....as I normally get a min of 12 mixed big bags delivered at a time....
BUT I always make sure there's a spot where left over conc can be used up without waste........

 

[julianf]

Access here is rubbish, so the only way to get reddy mix is with a dumper or pump also, and I've never bothered.

Garage slab is 5.5m x 3.6m by 6" deep and we were (surprisingly) done by lunch time - two of us on two mixers.

I don't mind mixing, but it's (probably / hopefully) the last bit I'm going to need for sometime and I don't want a half dumpy bag lurking about for ages.

I was considering buying small bags so I could take back the excess.

 

[lincoln2013]

Builders buckets are usually 15 litres, if that helps.
Dumpy bags are supplied as 1 tonne nominal weight so they can vary quite a bit which doesn’t help when trying to accurately quantify a job. I have always been put off buying small bags of agg because of cost so can’t really help with them.

 

[Erie Fred]

I always use 3-2-1
Your 4-1 has no sand ?

 

[Agrismith]

Take the volume of the hole you want to fill and plug it into here whilst selecting all in ballast.
It will give an approximate tonnage . A bulk bag is around 800kg.

Aggregates calculator

Use our aggregate product calculator to get your approximate value of sand, gravel, ballast and Gabion rock volumes.

www.aggregate.com

 

[Agrismith]

I always use 3-2-1
Your 4-1 has no sand ?

Our sand and stone comes pre mixed to the correct ratio

 

[gaz1]

julian are you mixing by the bucket or by shoval ? into the mixer

a note here i use 1 1/2 gravel to 1 sand but some adjust that to 2 gravel and one sand it depends on the ratio of gravel that you want mixed

i can adjust enough using those mixes to getting that cement right but thats also depends on how white you want that cement

then its your adjustment of water content used in the cement mix

these was done by a wheel barrow mixing

 

[Pigeon_Droppings2]

My mate is a builder...he usually sends me the measurements which I convert into volume of wet mix (in cubic meters)...I then plug it into one of the many sites to convert to dry mix and then into kg of cement and aggregate...which gives the number of cement bags and grab bags of ballast.

It's usually pretty close too....basically what @Agrismith says above.

 

[Erie Fred]

I bought plans to build a small volumetric cement mixer.
You just keep the (3) hoppers full, and out pours a continuous stream of mixed concrete.
I have not built it as of yet.