vibrating poker

[deuce22]

Hi.

I am pouring concrete in strip foundations tomorrow and just wanted to clarify if it is best to vibrate it with a poker.

Some say yes and some no.

I would do it on an oversite slab or similar, but I'm unsure if it's needed in the foundations.

I am trench filling to around 750mm.

Thanks.

 

[cotswoldbuilders]

You dont need a poker on standard footings.

 

[deuce22]

Cheers mate.

 

[theoldun]

Founds. No.
Standard oversite. No.
If using ready mix in founds and shooting straight out of bin into trench, then use trench flow mix. Get the driver to add more water and she will run round by herself.
oldun

 

[simonjay]

Founds. No.
Standard oversite. No.
If using ready mix in founds and shooting straight out of bin into trench, then use trench flow mix. Get the driver to add more water and she will run round by herself.
oldun

Trench flow mix does flow, but I got slightly different levels either side of some shuttering around a sewer pipe. Had to be bricked up differently either side (first couple of courses) !
Simon.

 

[theoldun]

Trench flow mix does flow, but I got slightly different levels either side of some shuttering around a sewer pipe. Had to be bricked up differently either side (first couple of courses) !
Simon.

That was not the fault of the trench flow. That was your error.
oldun

 

[deuce22]

Hi.

Thanks for the tip.

I'm assuming that when you say trench flow mix all I am doing is asking the driver to add water so that it will almost self level.

I was told that this takes some strength out of the concrete. For this reason they had a self levelling readymix (that they were calling flow crete) that was made so that it did find it's own levels but there was an additive added so that no strength was lost.

However there is a difference of £79 and £122.

Can I just clarify that adding more water to let it flow easier will not hinder the strength.

Thanks.

 

[theoldun]

Hi.
However there is a difference of £79 and £122.
Can I just clarify that adding more water to let it flow easier will not hinder the strength.

We do not know what company does Flow Crete as they all have different names for self levelling concrete.
Do not understand what you mean by £79 and £122. Are you saying that they are charging an additional £43 a mc or £43 a full load?
You are correct self levelling concrete is a designed mix.
Self levelling is only beneficial if you are pouring straight from mixer into trench
You can not wet down a GEN 1 mix to make it flow.
Adding any water to the mix slump does decrease the strength slightly, but it is common practice on site.
Your choice.
oldun

 

[deuce22]

Hi oldun.

I realise that names are different from brand to brand.

£79 is for standard concrete for footings and £122 was for the self levelling mix.

We are pouring straight into the trench using a truck with a 15m belt. I don't really want to pay the extra £946 by using the self levelling mix, so I am interested in the best way to pour the standard mix.

Cheers.

 

[theoldun]

Sounds like you are using a volumetric mixer supplier and not a drum mixer supplier. . If so a volumetric has not got a 15metre long chute. Standing ar*e end on they only have a 6 metre chute and when fully loaded they weigh in at 40 tonnes which will ruin most residential drives. Length approx 10.5m and width overall mirrors 3.15m
If we knew how many metres you are pouring and how far away from excavation, then could give you advice.
oldun

 

[deuce22]

I am pouring 26m3.

They are coming with 3x6 metre wagons and an 8 metre with a 15m long boom.

They are all drum mixers.

Cheers.

 

[theoldun]

Fair enough 26m3 sounds like 4 bed new build.
You have not said distance of pour from lorry. Can lorry get all round. Chute on 6 metre wagon, with 3rd chute on reach approx 3 metre from back of wheels but possibility of collapsing banks.. 8 metre is usually on 8 wheeler and never seen one with 15 metre chute.
oldun

 

[Hugh Jaleak]

There are a few drum mixers about with a conveyor that 'folds over' the truck. Faheys Concrete of Cornwall run one, (saw it out and about when on holiday last month.) Interesting concept, conveyor unfolds and extends, allowing the concrete to be placed up to 17metres from the truck, and negates the need for a pump on some jobs.

Think Faheys machine was made by a French firm: http://www.theam.com/UK/theam-produits.php

 

[Norcon]

We use this swinging on the end of a 22 ton Daewoo. Can empty a 9m load in 15 minutes.

 

[deuce22]

Yes it is the type with conveyor folded up.

It will be able to get all around the trench.

It's a 3 bed property, but the ground was pretty loose and so some of the trenches are over 600mm wide.

This is the type of mixer I mean.

http://media.diynot.com/147000_146482_38553_92304578_thumb.jpg