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Pigeon_Droppings2
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Layers....do you mean sections?
Might depend on what it's for....for my flat pack garage it has a raft that's steel reinforced and was poured in 2 sections.
Might depend on what it's for....for my flat pack garage it has a raft that's steel reinforced and was poured in 2 sections.
Smallfry
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No, not sections. It is for the house extension on a sloping site. semi underground garage and retaining wall.
Will use around 27 m3 of concrete plus a motorway bridge worth of reinforcement.
Access is very difficult. Narrow lane and mixer cannot get in the drive, so I don't know if it can all be done in one day.
Would be easier if I could do the understructure first, and then cast a slab on top. I don't see a problem with this, but .............
Pigeon_Droppings2
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The question i'd be asking...is it worth the effort?
I would think that whoever is doing all the calculations for the structural elements would probably be best to advise.
I would think that whoever is doing all the calculations for the structural elements would probably be best to advise.
Bobtail4x4
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if it was just a toe beam and then move shuttering once stiffened up, as long as its done in a few hours it will knit together, otherwise no,
as bob says hire a pump and sort the conny trucks on a return trip basis, otherwise they will be sat queueing and charge a waiting time,
as bob says hire a pump and sort the conny trucks on a return trip basis, otherwise they will be sat queueing and charge a waiting time,
Smallfry
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I know this would be the preferred option, and it will be needing to be pumped anyway, but this involves the lane being blocked for several hours, and will need at least three mixers worth.
The excavation was done years ago and never finished. It was also overdug, so I need to raise the level somewhat. It is on pure chalk, so I thought maybe I could cast the understructure more or less on the surface of existing surface, then do some infill and then pour the slab over this.
Structural engineer has massively overspecified because of this, but am hoping for some input before I go to building control with it.
Smallfry
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They can pump that far I think. They ban also pump vertically. If you want much more than a cubic metre, is in not worth the hassle of wheelbarrowing it, even less mixing it yourself. Ready mix costs just over half what it would cost to buy the materials to mix yourself, with no effort. Its a no brainer.
Smallfry
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Yes, it will be worth the effort. If it were an easy site, and the hole not overdug, I would not be asking the question !
More Amps
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AI says, "Concrete can be pumped horizontally for over 1,000 metres (3,280+ feet) using high-pressure static pumps, while typical line pumps generally reach 100 to 150 metres. Boom pumps, which utilize an extendable arm, can typically reach between 20 and 75 metres horizontally. Distances depend on concrete mix, pump pressure, and pipe layout"
Have you got a photo of the engineers drawings?
Smallfry
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They are part of the plans, but will try and sort something out
Smallfry
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Dont know if you can figure this out.
Any" joints" in the slab would be horizontal. Between the edge thickening, sheer key and centre web, and the 250mm top slab
Agroshield
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Will the joints have reinforcing projecting from them (i.e. vertical bars)?
On any building site which is supervised, the laitance form a concrete construction joint needs to be removed before pouring on top of it. This is as much to stop moisture tracking along the joint and corroding the reinforcing as it is for structural strength.
Traditionally this was done by scabbling, and since HAVS received more focus, that is now frowned upon. Instead, a retarder is applie to the joint and it is jet washed or wire brushed the next morning.
As above, show the reinfocing drawings and indicate on them where the construction joints would be. Just the structural drawings alone, without the rebar ones will not give you the best answer.
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If you are pumping 80m long, you have to allow for the concrete in the pipe when measuring. You also have to dispose of that concrete somehow. The pump will need somewhere to wash out - we used to make a tray out of four scaffold boards and line with 1200 ga. DPM.
If you want a good job, tell the concrete supplier it will be pumped and buy a pumpable mix. Otherwise, the only way to make it pump is to add excess water, which compromises the strength.
Gareth J
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What does dumper hire cost? You'll definitely be able to outpace the time taken to lay with two dumpers, probably be ok with one decent sized one. Even better would be a construction telehandler with a good boom extension and a controllable dump bucket on a jib. Although a concrete pump will get it just about right where you want it.
3-4 loads in one day isn't bad if it's not too fiddly. Concrete suppliers will often do early loads to accomodate longer days work if needed.
3-4 loads in one day isn't bad if it's not too fiddly. Concrete suppliers will often do early loads to accomodate longer days work if needed.
Smallfry
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Yes, the joints would have projecting rebar, actually the top of the horizontal foundation beam cage.
Not being a concrete pro, I have never heard the term "laitance", so thanks for that ! I was aware of the existence of it though, and when we cast a retaining wall at the top of the garden, scraped it off before it had set, although at the time, my thinking was to roughen the surface for the next pour to bond to !
Now I am aware of it as a problem, I can remove it.
What is HAVS ?
If pumped from road, distance would be about 40 metres. I have a pump man coming Tuesday to discuss the job and go through the options.
BiL has an ancient 3 ton dumper, and like the vulture he is, the pipe washout can go in there, and he will "helpfully and at no charge" take the excess away for one of his projects.
