Any views on using Fairy Liquid in a concrete mix

Hi - In a nearby housing development I have noticed the builder is using Fairy Liquid in the concrete mix used for the footings of a new house. Does this have the approval of the building inspectoater and why would you want to do this anyway? I am sure someone will have the answer.

The addition of Fairy liquid in mortar used in bricklaying aids the workability of the mortar, haven’t heard of it being added to concrete mixes though, I think that it is frowned upon by authorities because apparently degrades the final strength of the mortar, apparently affects the chemical process. Dave W

It used to be common practice. Washing up liquid is cheaper than "proper" plasticiser.
It works by lowering the surface tension of the water. You only need a tiny amount. Don't really see it having much affect on the strength. The main ingredent in plasticiser is sodium lauryl ether sulphate

https://www.everbuild.co.uk/wp-content/uploads/2014/03/SikaMix-Powdered-Mortar-Plasticiser.pdf

The main ingreadient in washing liquid is sodium laureth sulphate the same thing

https://en.wikipedia.org/wiki/Sodium_laureth_sulfate

Robert G8RPI.

There are approved plasticisers for mortar/concrete, and I'll bet they are not a lot more expensive. According to wikepedia correct use actually makes concrete stronger as it reduces the amount of water needed to make the concrete flow, and excess water makes concrete weaker

wiki

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Back in the 1960's we used Daz.

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Not unknown for the fairy bottle to be filled with proper plasticiser as it's easy to squirt a bit into the mixer if mixing on site.

Although not really needed for domestic footings plasticized concrete is available from most good ready mixed companies and has it's uses.

Best bet is to buy something like Mastercrete which has the additives already in the cement for when mixing mortar or render then you get the right proportions

Could you tell me where to buy Fairy Liquid for less then £3.00 for 5 litres please.

https://www.toolstation.com/everbuild-201-mortar-plasticising-admix/p60707

Not a concrete technologist but I would have thought the danger is weakening the concrete with too liberal usage causing foaming.

Bill D.

Bet the mixer is sparkling clean and the builders have very soft hands though.

I have used it with cement on a syringe made for injecting it. Without a small ammount of plasticiser, it would be impossible to use. PVA adhesives are also useful in the cement mix, it enhances the adherance to older concrete.

Enough to form bubbles will very much increase the workability of the mix. Not good for the strength as concrete relies on good compaction for maximum strength development.

Masonry cement, for brick-laying, etc incorporated an air entraining additive to improve the workability and use of mortars where ultimate strength is not required (mortar should be weaker than the bricks/blocks). It is far better to replace brickwork pointing, if building movement causes cracks, than replacing bricks🙂 .

Far better to use the correct additives, approved for the job, than washing-up liquid.

I once had to visit a concrete user who had found low strength concrete (cube testing) results which had been used in concrete pilings. The bulk cement had been delivered by a tanker previously used for washing powder product/ingredient. The concrete pilings actually smelt of ammonia (which presumably retarded the setting of the concrete). I don’t know if later strength tests were accepted or if the pilings had to be replaced. An expensive exercise.

The concrete supplier knew the cause before I arrived - he already had cement samples and cube test results - and I knew of the outside contractor that delivered the dodgy load to the depot - before it was transferred to a company tanker prior to final delivery to the ready-mixed concrete site cement silo. Those pilings might still be propping up something in Linford (now part of Milton Keynes).

Edited By not done it yet on 24/05/2021 20:23:03

I have run several 4and 2 gangs of bricklayers and fairy is not used in concrete but is better than febmix in mortar and if you lay bricks with our local sand you would be pleased to add a dash of fairy .Used it for all of my fifty years in the building trade and of all of the washing up liquids fairy is the cheapest and best in the long run as you only use a squirt,and after all this time 10years since I retired I havn't seen any deteriation in the buildings I worked on.

Frank

As a plasterer's mate I used a few drops in a mixer load as a deflocculant to prevent the mix balling.
Mainly happened with dryish mixes like floor screed.
Never used it with concrete.

Veering a bit off topic, but still related to additives... when I was at polytechnic, one of our lecturers was heavily into researching cement additives, and had a number of examples of what was possible. The most impressive was a coil spring, made from sand, cement and additives, about six inches in diameter and height, probably about three turns, which acted in all respects just like a normal steel spring (possibly not as long a life though).

And the flat roof of a power station admin block I worked on had a foamed cement mix laid on top for insulation purposes - specialist mixers were used, don't know what the additive was.

Back on topic, yes, Fairy liquid works (never heard of it in concrete, only mortar), but builder's merchants don't sell it, so just order Feb whilst you're getting all the rest of your stuff delivered

Rob

There are additives for concrete to make them flow more easily when being pumped or into areas of dense reinforcement... Normally added once the mixer is still on site as it gets very sloppy.... Tarmac call it TOPFLOW, hanson call it easy flow... I had some awkward footings built with limited access and it saved us the cost of a concrete pump, just pulled it along with a rake.... Much preferred structurally to adding lots of water.

Yes I too remember Daz in its powder form back in the sixties. Wasn't liked and would be restricted. I don't think too much would make a difference. Certainly helped to ease working the mortar, but that was alongside very hot bricks straight out the kiln and hosed down, dry sand lying in heaps on the ground and all sorts of other bad practises. Nobody seemed to care. Look at the London flat fire block proceedings 50 +years on......absolutely terrible. If you are responsible, then you are responsible, sharpens the mind no end. O dear perhaps I am too old now but have seen things that would make you seriously cringe. Stay safe everyone.

I have heard that washing up liquid can cause excessive corrosion of steel in concrete, this may be total rubbish as I have no authoritative source to quote and irrelevant if no reinforcement is used in the concrete.

Mike

Seems feasible as there's a lot of salt in it to thicken it, but then again, cement is a bit on the corrosive side anyway. Some more so than others.

Rob