Concrete mixing tables

[HiHo1]

Hello, could anyone point me in the direction of these? I need to mix up some C50/RC50. I think it's 400kg opc/tonne, but not sure about sand/aggregate ratios.

And it would be useful too if there are any calculators or tables so I can work back from volume of castings required to weight of dry materials (for purchasing), and from weight of individual dry materials back to their volume (for mixing)!!

Thanks!

 

[^woody^]

Tables are too high. Mix on the floor or use a mixer

I doubt that you are doing some civil engineering bridge work, so just do what everyone else does and use buckets or shovels to measure. 1:4 for your C50 mix

 

[HiHo1]

Thanks, but I was talking about the numbers type tables....I can't seem to find any to help.

With your 1:4 example, isn't that going to produce something more like C20? And also need the sand/aggregate ratios.

I'm building a cantilever retaining wall, and the spec calls for C50 so need to get it right.

 

[^woody^]

You wont get c50 unless you have it batch mixed by a proper company

Has your engineer just specified this to cover his own back?

1 cement, 4 mixed gravel from a big bag of mixed gravel and vibrated will give the strength you need

If this needs to be exact strength, with precise mix, and fair-faced and reinforced, then you need to go to a proper supplier and give them the full specification

 

[HiHo1]

It's what the engineer specced - probably OTT, not fair faced but is reinforced.

But even if it is over engineered, surely there's a very big difference between 200kg opc/tonne and 400kg opc/tonne?

Can't have it delivered (economically) as it has to be poured in stages as the blockwork goes up.