OT - Concrete Buggy v. Pump Truck

Thanks all for helping me thru my myriad of concrete questions...

...latest burning question revolves around moving the concrete from a truck to be placed in the slab.

A couple of specifics, 25' x 40' size, only accessible on 2 sides due to existing buildings. There will be a stem-wall sticking 8" higher than the finished floor, around the full perimeter with a cut-down for a 9 foot garage door. Expected pour of 18-20 cu yards for 5-6" slab. Field of #4 rebar tied 16" on center throughout the slab, on 2" chairs.

Calling various ready mix places they all seem to agree on the cost for a pumper truck being in the close neighborhood of $1k.

The concrete truck chute would seem to have a range of around 15 feet but that is a long way to move seeing that only half of the area is directly accessible.

I can rent something like a Whiteman (its a brand name...) gasoline powered concrete buggy around $120-150 per day which seems like a lot of savings.

The functional sticking point is traversing the field of rebar with the buggy. It seems like if I layer some sheets of plywood for support of the load (estimating 3/4 yard @ 3000 lbs + buggy weight) and then suspend the ply above the rebar grid with something like a group of 2x6 or 2x10 blocks laid flat between the spaces of the grid, I could accomplish it via having a buggy driver dedicated to running back and forth.

I also don't have a good feel for how much concrete is "wasted" in priming the pump truck..the booms are like 30 meters/100 feet so it seems like there would be some extra that would have to be ordered.

So I seek the sage advice of the membership...spend the extra for the pump truck, use the plan above, or something completely different? Thanks in advance.

You should have at least 4 guys to help pour this job. Back the trucks up as close as you can without touching the forms or distorting the dirt enough to affect the forms and pour it out. Use come-a-longs to drag the concrete over to the opposite side. ( your helpers should be young and strong and willing to work)Pour it wet enough so it will flow but use as little water as possible. If you want to wheel barrow it then drop the rebar off the chairs and pull it back up as you work your way out. A pump truck or even a trailer pump is overkill for a 20 yd. pour unless there is no way to get to the forms. The pump will waste about a yard. Or you could hire someone who knows what they are doing. You only get one shot with concrete and concrete waits for no man.

Listen to rbdjr59, he is correct on all points.

on the 40' sq hangar I have posted pic of, access from
one end only, and had to go under 11' high door header.

Got telebelt equipped truck, could reach in the 40'.

Pump way overkill. If no telebelt truck avail use
(2) power buggy's.

I did a press foundation, about 50 yards, (2) guys
on power buggy's moved all of it about 500' thru
a manufacturing plant, and never kept the trucks waiting.

Try and find a Telebelt. I would charge our minimum of 550 to place that slab. No waste no shoveling your back will thank you.

I would think that a pump truck would be just the ticket for pouring that knee wall. Just guide the hose right down the forms. No "aiming", no spillage.

And agree on getting the rebar down on the ground before you try to drive over it. Just pull it back up a little as the concrete works its way across. The concrete will hold it up. No need for chairs at all.

Are going to pour the job yourself or hire finishers?

It makes a difference in the labor cost if they have to also place the concrete by hand...
Unless the trucks can back up to the forms and shoot the concrete to the other parts of the slab with long chutes, I always have a pumper. Saves labor, damage to the forms and makes a job go faster.

A few times I have made a portable "extension chute" using saw horses, 2x12 for the bottom and 2x8 for the sides. Truck puts on all his chutes and then we moved the extension to the end of his chute and he pumps into that. Able to get about 12 more feet that way.

Leave off a section of the forms, back the truck over the rebar(no chairs), discharge the concrete, pull up the rebar (preferably using hooks), drive the truck out of the forms, replace the last piece of form. No pumper, no power buggy required. Just be sure you have someone dedicated to pulling up the rebar.

Here a pump is 500-600$ these days, used to be $400+ $4/yrd. I've been told between 1/2 cu/yard to 1 yard for the pump, 1/2 seems more right from what I've seen.

When we did my slab last year, 24x34, 9+" thick(about 25yards) with walls/ceiling already in place, we just backed up the truck to the 9x12 door, they can only use 3 chute sections here, not allowed to use the last one(they're not even on the truck or they get fined) so we only reach maybe 10' . Anyhow, we were I think 4 or 5 guys, we used a plank and my sturdy wheel barrow to reach the furthest back corner to start things off.
Everything else could be reach with a rake/shovels. You do need to be enough guys, preferably a few that are used to doing this.

Even with a pump its not an easy task, it usually goes much faster and you need to haul ass. 1 guy on the hose, 2-3 leveling/smoothing.

Even if you get a buggy for a small slab like that, you'll do what, 2-3 loads with it and chute/rake the rest, mostly if you can back up right to it and be roughly centered.

It is hard work though, so people who health conditions and heart attack prone... either have good life insurance to pass onto the kids or hire someone.

Thanks for all the replies. I like the idea of a wooden extension chute the most. What kind of a slope do you put on it and do you have to drag the concrete thru or is it still gravity flow?

I don't like the idea of trying to pull up a field of rebar. I'm not that experienced but my gut tells me its "corner cutting". Its probably "good enough" and fast, but since I only get 1 shot to do it right I'd rather put it where its expected to be.

Trying to maneuver the truck which is likely close to 8'6" wide thru a 9'3" or so opening in the corner of the stem wall (for the garage door) around to the other part of the project also does not seem like its primed for success.

Estimating the buggy would be used on 1/3 to 1/4 of the pour, if I could get around 22' of chute, measuring in from the wall, I think it would all work out via chutes.

Just set a heavy duty saw horse up at the end of the trucks chute and place your wooden chute on that . Let the other end rest on the ground. That will give you about 34 inches of fall. If you have some heavy vapor barrier plastic left double it up and drape it over the chute to make it more slippery. Depending on the wetness of the concrete, my guys like it dry, you might not have to do a lot of raking.. set your chute up, pour a corner then swing your chute to another area.

I would still rent a pump

Go with a pump, watched the neighbor do a job. The driver shoved some newspaper then filled it with water to pump out the rest of the concrete wasting very little.

For starters do yourself a favor and hire a concrete contractor. Doesn't matter if you 20 helpers if they are not experienced in placing and finishing concrete.Let the contractor decide how to place it. If they buggy they will set up with the proper benches and planking. If they decide to pump then the mix will have more cement and when done some concrete will be wasted that lies in the hose.

I agree with Mike 44 -- get a good concrete contractor to do everything. Let him decide the best way to get the job done, especially if you have things like fasteners, drains, etc., embedded in the slab. You definitely do not want to have to do the job over or make corrections.

(When the contractor did my 80x50x6 inch thick slab, he brought in a brand new, giant pumper that had a reach of something like 100 feet! It was amazing how fast they got that thing poured without having to worry about "lifting up rebar", etc.)

mike 44 said:

For starters do yourself a favor and hire a concrete contractor. Doesn't matter if you 20 helpers if they are not experienced in placing and finishing concrete.Let the contractor decide how to place it. If they buggy they will set up with the proper benches and planking. If they decide to pump then the mix will have more cement and when done some concrete will be wasted that lies in the hose.

Click to expand...

ABSOLUTLY ..... 100% correct..... if the crew is experienced working with each other, you're golden and you get a VERY GOOD JOB...

If they have learn on the job ??? .... YOUR NOT GONA LIKE THE RESULTS...
remember, you're gona LOOK AT THIS and WALK on it for a very long time...

Did not mention, have a coworker who has built 3 buildings on his property, he has used the same concrete guys for all of them and everything is great. There are two skilled guys, my coworker and a friend of his made up the additional laborers. I plan to use the same guys and be one of the laborers. obviously I will take a heavy dose of direction from them. Just like to think thru the possibilities up front and make a plan. Even if it gets shot full of holes I get to learn why my initial plan sucked and what methods are better.

You don't say what kind of trucks you have to deal with.

A front discharge truck will have a 20ft chute and he can blow it out
another 10ft.

Talk to your supplyer about plasticiser. It will make the concrete run like water

but does not make it weak.

Don't do it your self. Three guys that know what they are doing can do this

no problem. I am too old now, but when I was pouring with one helper with experience is all I need.

Get front discharge trucks they can pour it for you just stay to hell out of the way.

I have never pumped a slab in my life, and that's a long way from a big pour. Kenny

You need to see the big boys do it.

11 guys and one laser screed poured 1000yd a night for three nights running.

Another factor is how long the trip from the concrete plant to the job takes and how long it takes you to place the concrete. You are supposed to have the concrete out of the truck and placed within 1.5 hours of when the water is added at the plant. I've seen loads rejected by the engineers when that time limit is exceeded.. There is a semi loophole that says you can exceed that time if the purchaser says the slump is ok to place without adding extra water.. Nobody I've been on a job with wanted to take that responsibility

Just how good of shape is your crew in? With the shape I'm in, I hire a pump

If it were me, I'd rent a 12' metal concrete chute from a rental yard, maybe even two. Much better than a wooden chute because they're lighter to move around and concrete flows through them more easily, a major consideration when the angle is low because you're trying to reach that back corner. Metal chutes rent for $25 a day around here and can be picked up at the same time as the power trowel. Set the truck end of the chute on a sawhorse and the discharge end on the rebar and you should be able to reach almost all the way to the back, dependent of course on how much chute the truck carries, which is something the dispatcher can tell you over the phone. As Sicero says, a front discharge truck is the way to go, partly because the discharge from a front discharge truck starts out higher than on a rear discharge truck.

Some moving of concrete by hand is necessary, but try to minimise it by intelligent process. That stuff is heavy and there ain't no sense in working harder than you have to. There's always plenty to do on a pour without doing makework.

Sequence the trucks and let them wash their chutes out on site, but that's all. No dumping or washing anything from the drum. You don't want hardening concrete meadow muffins to deal with the next day. Dealing with their chute washouts is enough work.

And it's after the concrete is placed, screeded and bullfloated that the fun begins. 40 x 40 is a big slab to finish all at once, especially if it's a sunny or hot day. It'll be hard for one trowel to keep up with the concrete, and I'd do it in two pours for that reason, but it's up to you.

When you trowel/finish, have at least two guys, and preferably three there. One to run the trowel, which will probably be continuous once you start, one to hand trowel around the edges and one to spell the other two and act as a gofer. You'll have to go over the concrete at least 5 or 6 times including edges to get a decent polish, so the finishing takes awhile. I can tell you from personal experience that not being able to keep up really sucks. A rough finish is fixable, but it's unnecessary and expensive to fix.

One more thing (just in case you haven't had enough advice ). Do not, I repeat, do not, under any circumstances, leave the site before or during finishing. You will regret it, and yes, you can ask me how I know, but you don't really need to, do you? There is always something to be done, and concrete does not wait.

Good luck with your pour and let us know how it goes.

Neil

Conversation I had with my brother-in-law a number of years ago:

Me, "How did the garage floor turn out?"
He, "OK, but it's kinda rough."
Me, "What happened?"
He, "It was so hot, when we finished pouring, we stopped to have a beer."

The freakin' garage floor still has boot prints in it to this day.

Dennis