K guys ive ran into a few situations where ive received an unpumpable mix, did everything i could think of to get her going and she just wouldnt pump. I run a Reed B70 line pump with 2 1/2" hose...

is there a general rule when it comes to unpumpable mixes? Like is there a rock content level thats kind of the limit before you need additives such as pump aid?

if i was to look at the ticket of the mixer driver, generally should i be able to read that and know if the mix will pump? if that is the case what exactly am i looking for that will tell me if its obviously unpumpable

with 2 1/2". you're looking at 1/2" aggregate max. probably 60% sand to 40% rock ratio. 5 maybe 6 sack mix. It's not up to the pumper to MAKE it pump. The customer should specify a pumpable mix, but they need to be aware of the size of your line, therefore max. rock size and stone ratios and cement content. The RM plant should be made aware of this too. It is simply amazing how little the people that work with concrete every day actually know about it. Do they not learn about advances in the industry? I guess they figure that they are like doctors, no continuing education in that field it seems, either. I've recently had people in the industry for 6-7 years not know what a super plasticiser was, or what a water reducer does, or just how air entrainment is achieved, I find that hard to believe, but it IS true.

I work for a small RM/pump company. I rarely pump anyone's mud but ours. Still, when the line pump goes out our contractors are required to order a pea gravel mix (1/2" minus), 60 rock, 40 sand max, and six sack. Otherwise, the pump doesn't go out. Anything rockier or less rich is just to damn hard on the equipment, besides all the contractor does is bitch about all the plugs. Paying the little extra for 6 sack saves them in labor by jobs end (though they never see it that way!!!).

just have this kind of unpumpable mix too late that it drops in my hopper.

Oh, wow!! That must be a finisher's dream??

thats very similar to what i had on friday.

we got the second truck to add more sand and less rock, and i had them both drop in some pump aid and it pumped better, still had plugs on occaision. But the first truck i didnt know it was unpumpable untill it was in my hopper and i tried to run the prime through...barely even made it through my metal reducers, we specified a pumpable mix  but it most definately wasnt.

I just want to learn about it so i can know by looking or reading the ticket.

Wow,tell them it's a concrete pump,not a rock crusher.Geez,look at all the jagged edges.The guys got it right,a 60 40 mix,nothing less than 6 sack,little flyash to help.

I disagree with letting the company do the ordering cause mix designs are very important part of pumping it never hurts to call the RM plant and ask how much cement and fly ash then ask how much size 78 rock and sand, and never say 1/2 inch minus ask for a rock size that will pass threw a 1/2 inch screen, I talk to every batch plant that I'm using today and do 99 percent of the ordering and delivery times, if you learn to do that you will have a lot less trouble.

And you have also taken on the responsibility for specifying a material, so now you've practically become a subcontractor instead of a service provider. Do you also pay for the concrete, and charge it back to the customer? What if it has some undesireable characteristics? Shrinkage cracks, curling? Your name will appear on the court documents then too.

Mathew had it backwards. With pea rock mix, 40% rock weight and 60% sand, plus 5.5 bag and a bag of fly ash. Also when you get that kind of arrow head crushed rock? All bets are off. Good luck..

Actually,if one thinks about it ED has a valuable point.Double checking whats coming at you is great,a chance to pow wow with contractor before a problem.

I don't know about the rest of you, but I don't have contractors or RM plants in my area that would take kindly into my medddling in their business. I would very quickly be told to mind my own damn business. But then again the contractors and RM plants here are quite good at what they do, seldom do I have major problems in pumping, primes sometimes cause an issue, I think maybe I need to prime out faster.

yeah i dont have that option, and i forsee guys not specifying pumpable mixes... So i need to be able to see what it is by reading ticket or by looking

another problem with that though is some RM driver tickets dont specify all the details. So reading tickets isnt really reliable. But it does always tell you size of rock, but not all tickets show you weight of rock per meters... and even if it did im not sure whats good or bad.

we do it in mm here. So when you say 1/2" rock thats like 13mm. But i notice its not always size of rock that makes it unpumpable sometimes its shape too...

but the main thing seems to be rock weight to meter or mud...

I also dont know what you guys mean by sack mix

In the US, a 'sack' (bag) of cement weighs 94 lbs (42.6 kg) in Canada, it weighs 40 kg (88 lb).  Different packageing standards. 

But these guys mean 94 lb - which essentially rounds off to 100, so when they say 6 sack, they really mean 600 lb per yard.  In Canada, in the larger centers, concrete is batched by the cubic meter,m which is 1.61 cubic yards, conversly a cubic yard is .76 cubic meters.   Smaller centers generally have stuck with cubic yards, and the Department of Weights and Measures doesn't seem to care about that.  Also, FYI: 1 lb=2.204 kg. 

The top one is American packaging, the bottom, Canadian.

Pumpjockey where I pump at no RM  plant puts the weights on the ticket I will not even try putting something I don't know about it will bite you in the butt every time, all the RM plants will call me if I don't call them first to ask me what mix I want we have a good relationship, then I can get them pumped out and back to the plant, maybe you guys should show a little repect the them and see what happens, a lot of your big city RM's think they know it all, and pumpers are dumb but it they would give you guys a chance all would be better, a little advice drive down and talk to them in person being nice goes a long way.

True enough Big Ed. I'm glad you have cooperative plants that are willing to work with you and learn about the in's and out's of pumping. Sometimes it doesn't take much to make a mix pumpable. I've always found that the better and easier it pumps, the easier it is on the placers and finishers. But by the same token, you can get it too easy and it cracks and shrinks and curls, you still need to remember the basics of concrete composition. Basically good mud pumps good, shoot for the middle, too close to the borderline and different problems crop up. Whether in workability/pumpability and concrete performance.

is it unreasonable to carry lots of pump aid with me and whenever im suspect ask if i can add it to the mix???

Like I said, good mud pumps good. If you are consistently having trouble with a certain plant's mud, then something needs to be addressed. It really shouldn't be up to the pumper to MAKE the mud pump. By adding something to the mix, your are taking on a big portion of the liability for the quality of the concrete.

Hello - your local REED Dealer is Joe Mautone...and he's only a phone call away at 403-861-3637. He'll be able to help you out with everything from oil leaks to mix designs. Call him ANY TIME!

Thank you.