"ARWadsworth" wrote in message
.uk...
Possibly a stupid question, but how many 25kg bags of ballast (with a 5:1
mix) would it take to make 1 cubic metre of concrete?

I really have no idea how to work this out myself.

Adam
The density of concrete varies but is generally taken to be approximately
2400 kg per cubic metre (2.4 tonnes). If you're using a 5:1 mix then divide
2400 by 6 units and multiply by five to calculate the mass of ballast
required for a cubic metre.

2400/6 = 400
400*5 = 2000kgs.

Therefore the number of 25kgs bags required would be 2000/25 = 80. I have
ignored the mass of the water to be added plus the moisture already present
in the ballast for simplicity.

I assume you're using 1 cubic metre as a unit volume otherwise you will need
to order in bulk as the man said.

AT