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Posted: Sat Feb 22, 2014 5:33 pm
by DNgroundworks
Hello everyone,
I have a job to do for a client which is basically a 2.8m square concrete patch on her driveway.
She wants me to dye the concrete so it is in-keeping with the rest of the ancient concrete and not a bright white colour.
Anyone any experience dying concrete? Can you even buy dyed concrete?
Posted: Sat Feb 22, 2014 5:49 pm
by TheRockConcreting
To answer your question can you buy ready mix colour crete then its yes you can, but no one will supply you an amount that small, your best option would be mix up your own colour crete onsite.
I use harristone because he is local, remember you must use CEM I and its normally 5% weight of cement, max 8% if you want it to be super deep.
Posted: Sat Feb 22, 2014 6:11 pm
by Tony McC
I'm not sure if you mean it's 2.8m² or a square with sides of 2.8m making it 7.8m².
At 2.8m² and assuming a depth of 125mm, that would need only 0.35m³ but, as Jay says, no-one would supply so little (or at least not at a sensible price) but if you site mix, maintaining accurate dosing of dye to create consistent colour will be a bit of a challenge. Use the biggest mixer you can find!
At 7.8m², you could need just around 1m³. You might get someone to deliver that as coloured ready-mix, probably one of the smaller independents rather than the big boys because churning out a cubic metre on consistently-coloured concrete in small batches is practically impossible.
You could, of course, just use the coloured concrete as a 20-25mm topping over the still plastic, freshly poured uncoloured or approximately-coloured base, but as I've already said, they key to success is a BIG mixer. 
Posted: Sat Feb 22, 2014 6:21 pm
by DNgroundworks
a square with sides 2.8mtrs, tbh im not really keen on the idea whatever colour we dye the concrete it aint gonna match the 50 year old cracked algea covered surface which is already there.
I have suggested that a whole new block paved driveway would be much more suitable :p
Posted: Sat Feb 22, 2014 6:29 pm
by mickg
use pig muck or yogurt on the surface of the new concrete
Posted: Sat Feb 22, 2014 6:32 pm
by lutonlagerlout
just give it the back of the shovel
soon match existing :laugh:
as you say no matter what you do will not match
LLL
Posted: Sun Feb 23, 2014 11:01 am
by GB_Groundworks
As mick said when we've done stuff like stone walls that need to match in with older mossy or algead walls we paint them with horse shit and water slurry or natural yoghurt gets the miss and algea going quick
Posted: Mon Mar 10, 2014 8:13 am
by DNgroundworks
Is there not something I could paint on the surface of the cured Crete? Something similar to a wood dye?
Posted: Mon Mar 10, 2014 10:26 am
by Tony McC
There are dyes for cured concrete but they are a) expensive, b) not particularly impressive, and c) not UV stable so they fade, some of them relatively quickly.
Quite honestly, The 'organic staining' ideas suggested above are better value for money. I usually add a few owld tea bags for that naturalistic earthy colour.
Posted: Mon Mar 10, 2014 11:05 am
by Bob_A
DNgroundworks wrote:She wants me to dye the concrete so it is in-keeping with the rest of the ancient concrete and not a bright white colour.
Could an acid stain be used?
Posted: Tue Mar 11, 2014 8:32 am
by Tony McC
Possibly, but the results very much depend on the aggregates used to make the concrete.
If the OP was a regular user of etching acids or acid stains, a trial panel could be done, but it's a bit expensive to buy in the acid just to see if it might work.
Posted: Tue Mar 11, 2014 1:12 pm
by DNgroundworks
Well I've Sawn a lump of Crete out of the driveway and taken it to a concrete dye manufacturing/supplies place, they said it can't be matched! They said the best thing to would be to use a concrete with castle cement as it has a fly ash additive, thus making it darker?
Posted: Tue Mar 11, 2014 2:08 pm
by Brucieboy
If you're trying to match algae-covered concrete, it's best to go with yoghurt / horse muck as suggested previously. If you decide to go down the fly ash cement route (Castle Sulfate Resisting or Lafarge Sulfacrete both of which are available in 25 kg bags / CEM II 32.5R containing 25 to 35% fly ash), it will make the concrete look a little bit darker than normal at the surface but will it still match the existing?