I’m researching concrete pour rates and everything I can find says things like:
“For example, when you pour concrete at 70 degrees F and a pour rate of 5 feet per hour…”
Do they mean cubic feet? I assume so, since it’s the only meaningful (to me) way to talk about pouring is based on volume - just looking for quick confirmation.
I would assume so too. It wouldn’t make much sense as linear feet since a ‘foot’ of concrete could be 1 inch or 3 feet thick.
It doesn’t make sense to me, considering the trucks often dump 8-9 cubic yards (216-243 c.f.) of concrete, which we can often unload in about 30-60 minutes time. And then spend a good part of the day working it and finishing it off. To pour at 5 cubic feet per hour is not quite 1/6th of a cubic yard. At that rate, it would take us over 48 hours for a 9 c.y. load. Do you have a link?
Maybe they are talking depth for certain applications?
In my experience builders usually talk about feet and yards when they mean cubic feet/yards. You can normally tell what they mean by context but when I had my drive done I was careful to make sure which was which. They should have been using centimetres and metres, but they were a bit old fashioned.
They are talking depth. The reason why they talk depth in concrete pours is that you can pour a larger depth of concrete in a single pour than the formwork can support if you allow the concrete at the bottom to set-up and start to cure. If you pour the entire depth of a deep structure in one go the liquid concrete might exceed the pressure the formwork can hold. But if you limit the rate at which concrete is added - in terms of height per unit time - the lowest parts of the pour cease to act as a liquid, and you can pour a deeper structure in one go. Single pours are much stronger to the point of being required in some structures, so this is important.
In commercial and industrial construction the standard unit of measure for a concrete pour is in cubic yards, or CY. Outside the US it is in Cubic Meter. Only in residential or light construction would you see someone list a production rate in lineal feet.
The production rate varies by a number of factors.
Are you pouring footings, walls, columns, slab on grade or an elevated slab? The productivity per CY will vary for each.
How does the concrete get from the truck to where you want it to be place? Can it be placed off the back end of the truck, or into buggies and moved that way, or from a concrete pump, or do you need a crane? The worst case would be to move in wheelbarrows. I did that as a kid but seldom see that done on a jobsite now, except for the smallest of pours. Once again the pour rate will vary for each type of pour method.
Finally the concrete has to be finished. You don’t just put concrete somewhere and walk away. The finishers have to do their work. If it is a footing, or column or wall it is a small part of the cost. If it is a floor slab it is a major cost of the placement.
Then there are different types of finishes. Broom finish, which you see on a sidewalk sometimes. Hard trowel finish, and then there are ultra level floors which is a big expense. Finishing is usually expressed as a separate cost and usually measured in SF. I just listed two, but there are many different types of a concrete finish.
A contractor will look at all of these individual factors in considering the cost of the concrete placement. Each activity gets taken into account, measure by how much there is and then priced. The final total is the sum of the individual aspects of the pour.
The actual “pour rate” of concrete per hour is just one small part of the cost factor.
Just a WAG, but lineal feet might make sense for a continuous pour on a large project (i.e., dams) where you don’t want the concrete to kick at the surface due to interruptions and you don’t want the heat of having the entire pour kick at once.
Thank you - that explanation makes perfect sense, particularly in light of the context in which I read the original quote.
http://www.allcostdata.info/browse.html/033720010/Placing-concrete,-see-03326-for-material-costs
Check there for some free online cost of concrete pours.
All measure is in CY, but if you look at the detail and you can do a little math you can figure out the MH per CY they are using.
btw…do not use this cost for any project. Or rather, i would not. As said in previous post, you need to look at all the facotrs per pour and all the individual aspects and cost each out.
Thanks for the info, but I’m not costing a project out at all - I need an example of a rate of change for an algebra class I’m teaching and was curious about this particular rate, that’s all.
Need answer fast?
