Casting patio slabs - mix - Is all-in ballast a good idea?

[james_joe90]

Hi all,

I shall be casting slabs in the new year, once my hernia scar seems strong enough

I intended to mix Sharp Sand, 10mm Aggregate and Portland Cement(3:2:1 ratio) until a mate recommended all-in ballast.

Is this worthwhile? I'm not sure whether it will be the right ratio of sand+aggregate and 10mm size.

I shall also be casting Ballustrade - can the same stuff be used?

If i must use separate aggregate - what's the best/cheapest stuff for slabs and ballastrade?

Appreciate any advice.

Cheers

[Tony McC]

No: you have no control over the ratio of aggregates that make up an "All-in Ballast". Some will be too gravelly; some too sandy, and some just right, a bit like the Three Bear's porridge. Consequently, there's no consistency when mixing concrete, and your batches will come out different colours, textures, strengths, etc.

[james_joe90]

Thanks Tony

i dont mind the different textures/colours as i'm after a natural old slab finish.

It's the strength i'm most concerned about.

i've heard builders sand is sometimes too fine and doesn't interlock very well...apparently ballast has more of a fine pebble sand which is better.

Anyway, think i'll stickwith mixing sand and aggregate.

thanks again

[Tony McC]

You don't use building sand to make a concrete. Read the main website and treat yourself!

[james_joe90]

sorry Tony,

i read through the site a while back (great content! especially the sub base info)

slip of a novice tongue i guess

[Tony McC]

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