An engineering problem for RE SNCOs

#1
Just got a job to lay a concrete plynth. Problem is the Res mong forgot the plasticiser. To keep the mix within CBM tolerence the setting time from green to hard has to be slow. How the hell am I going to crack this one. Bags of sugar and washing up liquid are an option but im not that experianced to judge the ammounts any advice would be gratefull thanks.
 
#2
Hairy_T_Towel_Holder said:
Just got a job to lay a concrete plynth. Problem is the Res mong forgot the plasticiser. To keep the mix within CBM tolerence the setting time from green to hard has to be slow. How the hell am I going to crack this one. Bags of sugar and washing up liquid are an option but im not that experianced to judge the ammounts any advice would be gratefull thanks.
Ask a Clk of Wks, sure a C will help you after your past comments :p
Love to help, but I'm just a jumped up E
 
#3
Depends of Qty of concrete and weather conditions (heat, damp etc) - but fairy liquid should do the trick - about half a standard Fairy ® TM (or Tesco's own brand) bottle per hand mixer load - whole bottle for Benford 10/7 (oh the replies that is gonna generate).

Oh, and keep to Fairy ® TM bottles for your next Blue Peter engineering projects.

SWAG it matie, unless you're apple polishing for a gong, but what do I know - I'm just a 'jumped up lance-jack' ClkWKs(E) :D

EDIT: Just get a load of Afghans to slap it with towels and blankets and keep spraying it with water from your Mum's ironing spray bottle.
 
#4
Well m8 the post is being gapped at the momment. I dont want to phone chillwel as they are mega busy. I will have to at last resort but Im at a funny unit m8 where tradesmen are not a plenty. Just wanted a quick fix online if you know what I mean. Thanks anyway.
 
#5
sexybomb said:
Depends of Qty of concrete and weather conditions (heat, damp etc) - but fairy liquid should do the trick - about half a standard Fairy ® TM (or Tesco's own brand) bottle per hand mixer load - whole bottle for Benford 10/7 (oh the replies that is gonna generate).

Oh, and keep to Fairy ® TM bottles for your next Blue Peter engineering projects.

SWAG it matie, unless you're apple polishing for a gong, but what do I know - I'm just a 'jumped up lance-jack' ClkWKs(E) :D

EDIT: Just get a load of Afghans to slap it with towels and blankets and keep sraying it with water from your Mum's ironing spary bottle.
It will be in the north of uk so damp and wet I guess thats the problem the last time I concreted was on my A1 bloody 10 years ago so I cant guesstimate as I have the 10% exrtra demanded but if I waste to much I will have to raise the level some how.
 
#6
Plasticisers only improve workability and do not reduce setting times. Sugar and fairy liquid actually damage the strength of the mix as it breaks it down. The hydration process is a chemical reaction that cures concrete - if you want to slow it down you need a retardent to slow the cure. I take it you need the plinth to be more waterproof? Then why not increase the strength to 35Kn?
 
#7
Increasew the ammount of cemment. Hmmm Yeap The plynth would have to be water proof. Its holding a 45 Kw Genny. If i increase the cement what about the aggregate and sand. Gives us a ratio. would I need to complete a slump test?
 
#8
Rifle-Green-Sex-Machine said:
Plasticisers only improve workability and do not reduce setting times. Sugar and fairy liquid actually damage the strength of the mix as it breaks it down. The hydration process is a chemical reaction that cures concrete - if you want to slow it down you need a retardent to slow the cure. I take it you need the plinth to be more waterproof? Then why not increase the strength to 35Kn?
...and don't we know a few in here too :twisted:
 
#9
Hairy_T_Towel_Holder said:
Increasew the ammount of cemment. Hmmm Yeap The plynth would have to be water proof. Its holding a 45 Kw Genny. If i increase the cement what about the aggregate and sand. Gives us a ratio. would I need to complete a slump test?
Suggest you find a CMT quickly as they can design it for you. Yes you need to do a slump test as otherwise you could be laying complete shoite, if it fails its your arrse.

Is it just a plinth or have you bunded it as well to prevent POL leaks getting away :wink: ????
 
#10
sexybomb said:
Rifle-Green-Sex-Machine said:
Plasticisers only improve workability and do not reduce setting times. Sugar and fairy liquid actually damage the strength of the mix as it breaks it down. The hydration process is a chemical reaction that cures concrete - if you want to slow it down you need a retardent to slow the cure. I take it you need the plinth to be more waterproof? Then why not increase the strength to 35Kn?
...and don't we know a few in here too :twisted:
Hang on SB, go firm mate.
Not sure about the mix H T T H.
Will have to contact a mate of mine.
He's on a similar job up in Scotland.
 
#11
and I suppose you are going to bund it? Actually, all you need for this is a 25 Newton mix as it is not underground and water retaining (like a basement car park)

25 N/mm2 mix (per m3)

Cement 340kg
Coarse aggregate 1100kg
Sand 750kg
Water 180 litres

You can do the maths for the size of plinth
 
#12
Hairy_T_Towel_Holder said:
Increasew the ammount of cemment. Hmmm Yeap The plynth would have to be water proof. Its holding a 45 Kw Genny. If i increase the cement what about the aggregate and sand. Gives us a ratio. would I need to complete a slump test?
Is gene to be mounted for working purposes or as a gate guardian (sentinal)? IF the latter then WTF ***** Beep?

Just carry out slump test after a few scoops in the bar after job complete. Failing that, go back after concrete is cured and spy whether gene has slumped. If gene stand up right and proud as punch - bish bosh, job's a good un - bull boots and line up for Medal.
 
#13
oh, and you don't need to do a slump test - that is only done when a CoW or RE test the mix on site when it has been delivered by mixer - just to keep an eye on quality.
 
#14
yeah the maths isnt a prob. To cure im using timber and polythene (spelt wrong) I never thought of bunding though. Because it will standproud of the formation layer I want a decent brush finish and earth falling on the top might mess that up.
 
#16
Hairy_T_Towel_Holder said:
yeah the maths isnt a prob. To cure im using timber and polythene (spelt wrong) I never thought of bunding though. Because it will standproud of the formation layer I want a decent brush finish and earth falling on the top might mess that up.
You could back fill around the finished article once the initial set is complete.
 
#18
Got to be able to retain as far as I can remember 3 x the potential leakage. Then you need a sump and a sump pump.
 
#20
MadPickleFarmer said:
Hairy_T_Towel_Holder said:
yeah the maths isnt a prob. To cure im using timber and polythene (spelt wrong) I never thought of bunding though. Because it will standproud of the formation layer I want a decent brush finish and earth falling on the top might mess that up.
You could back fill around the finished article once the initial set is complete.
Yeah but the satement of need wanted the plynth 0.3 meter high to tie in with an access maint path after that it will be backed filled but thats much later.
 

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