Greenpepper's Concrete CalculatorComes in Two Varieties:
Imperial Metric UK: Imperial
Australia: Metric
USA: Imperial
These
Calculator Pages are meant mainly for the Home Small Batch Concreter -
the guy doing a job at home maybe for the first time and not sure about
quantities or methods.
Pouring concrete, working with
concrete, is very satisfying, it is good work. And it looks very
simple: mix up the few ingredients and pour it, job done. There's more
to it than that. Much, much more.As you pretty soon begin to realise
when you start out on your first job. So all the help and clarity
you can get the better. That's why these pages. Hopefully they'll
help with at least part of the job: the quantities and perhaps pricing.
The main points of the method of calculation are these:
For Unit quantity of Concrete it is assumed 1.6 Units of Dry Materials will be required.
A 20kg bag of cement is assumed to have a volume of 0.01333 cu m.
A water/cement ratio of 1:2 is used and arrived at by taking 0.75 of the cement volume. This mix should be able to reach 20MPa
It
should be remembered that cement density can vary between 830 kg/m3 and
1650 kg/m3 - see the Portland Cement Association page.
Hence it is
sold by weight. But we are to use it by volume in our calculations.
So there's almost a built-in inaccuracy there especially when
working
with quantities smaller than one bag.
Now
I've been as careful as I can and I've checked and checked and I use
this calculator myself and work from it.: I think it is all good, the
calcs are correct and in support of that idea I've had no comments
contradicting it yet from anywhere.
But nowadays we must be
careful about what we offer so I have to print this caveat here,
explaining just what the situation is and disclaiming all
responsibility for any use you may put this information to.
Use At Your Own Risk. These pages have been put together
by a guy who is not a professional builder, engineer, concretor or any
other kind of tradesman. They may contain errors. The calculators may
give wrong results. The author accepts no responsibility whatsoever for
any harm or cost incurred by using the opinions and figures
expressed here. I can't. You must make your own
decisions and your own choices. Be warned. Be careful. Think for yourself. Get second opinions. Check.
Note: it currently calculates ONLY the basic 1:2:3 mix for a mix that should have a strength of at least 20MPa.
Please
email webmaster@greenpepper.org with any concerns: reports of
inaccuracy, suggestions for improvement, requests for
information or whatever.