Whats the leanest mix you can have pumped? I was under the impression around 3000 psi is about it. I was asked to pump 2500psi.

I have pumped a bunch of 2500 with my 47 (2525-6) and it was not happy unless the mud was pretty wet,Like 7 inch slump or better.It can be done but not as easily as the contractor generally thinks it can be done!!

Lean mix concrete or lean mix grout/cdf?

If I think there may be a problem I always confirm they ordered a " pump " mix! I know there are machines out there that will pump dirt and rock but I prefer not to destroy mine.

Here in florida we pump alot of house slabs at 2500 psi  Alot of times you have to ad water to pump it, but it will usually pump ok.

put a bottle of soap in the mix and it will pump like peanut butter every time---Pump on!

Mike, Out here in Calif.we pump a 2" slump at 2500psi every day, all day. The trick I found is to pump it slow, low volume around 4 on remote and to keep the RPM's around 1500-1550. Although it's much much easier with your grade of rock being river rock, not crushed rock. It also depends on grade of sand too.If too clean, it again becomes difficult. Call your contractor and tell them to add VMA to the loads. it's cheap and doesn't affect the mix design.

overhere in PR i pump alot of 2500 psi mix with no problems . but in each batch plant the mix is different .

2500 psi on boom, and 1.5 sac on pea gravel, u stop for more than 2-3 min and ur shakin and breakin the entire system, not to mention cleaning out the pump.

use fritz-pack read back of bag will tell you how to it. put in mixer in spin & pump away. make sure get your slump first then add.

we can do anything doesnt make it good most of the pumps these days can pump a wet 2500 mix 3-4 slump wouldnt happen down here I am very careful  if I am adding something to there concrete I dont want that kind of responsibility they need to add additives not blowing on you Bri thats just me I like the soap I have added that while doing flowfill it helps a bunch.but 2500 all im adding is water

Didn't believe it would work but pumped 2000psi with a schwing 52 for some rat slabs.

It will be 2500 with crushed stone 3/4". What is this VMA stuff? I don't know if they will want to change to different rock or put stuff in it, it is for a cheap mud mat type of deal. If I have to do all stuff that cost them $ they will use our telebelt, but they would rather use a pump (who wouldn't).

VMA is liquid sand, it cost about .25 per ounce you'll need around 12 ounces per load if that.ask your RM supplier to give you more details about it your pump will love you for it! anytime you add water your changing the water to cement ratio not a good thing to do, makes you liable for the pour.in fact adding soap also changes mix design too. Soap is a wetting agent, that makes water wetter. don't get caught adding anything to the mix let the supplier take care of it.

if they want to pump 2500 thru my pump there gonna let me add water or its a no go , if there worried about strength, pour a 3000, solves most problems, usually if they are pouring 2500 its a seal slab or something in that nature down here and they're really not worried about strength 

Pudg, are you willing to give up a 100+k per mo acct.? when they say "NO water", they mean "NO water"!! This customer has 80% of the work around here. I've been pumping this 2500psi stuff for yrs.It's used for the ftgs. I don't know about you, but I'm not giving this acct.away because I can't add water. Like I mentioned before it's an easy fix, add the VMA and PUMP-ON!! 2500psi @ 2"slump W/VMA = $$$$$$

i have pumped 2500 in most of the north east some time higher slumps help esp with smaller aggregate. with larger aggergate it may fall apart on you. some time leaving your hopper low so the barells do not fill full helps to. slick pak knocks the air right out of the mix. and soap is nothing but super air in the mix. we are there to pump there mud not to redesign it

Done 2500 quite a bit in AZ with a gate and rock valve.  Have also done dome 1500 lean mix here in the northwest.

Be careful using soap, it can spike the entrained air content and could get rejected if it's being inspected on site!

not too mention become a living hell for the finishers if they have to do a machine finish. I have had this experience first hand!

Too Tall, Thanks for the input, spot-on!! some just don't get it. Although I can't re-design the wheel!! I'm able to re-design the mix, by making a phone call to ready-mix. I'm really not re-designing mix at all. I simply ask them to juice it up a little with an additive (VMA) that doesn't change anything but the pump ability. Contact your local readymix for further info.

N2MUD,

No I would not be if it would pump,if it would not and your vma isnt available you add water thats what im saying,whats the cost of this vma ? would it be cost effective just to add cement ? just asking I have never used vma

Pudg, seems like maybe our discussion has headed south a little. I do apologize. To answer your question though (VMA)is cheap compared to cement or flyash.(correct spelling?) I know cement is about $6-8 a sack where as flyash isn't far behind.On the other hand VMA is only about.25 an ounce usually 8-10 ounces (per load) will do the trick. Unlike cement,flyash or water it does not change anything to the original mix design.no need for resubmitting design. We use it quite often around here because the sand is so clean.I mentioned earlier check with your local ready mix guys,perhaps they could explain it better than I. Since I know you have line pumps,It will turn those hard to pump jobs into pumping butter I promise. The on-site inspectors in our area are good people to work with, just won't allow you to add water.It's stated on the ready mix tags from contractor.