We have been pumping for this project for a couple years, and they make their own concrete but don't supply to anyone else. The concrete looks ok but, maybe a bit on the sandy side. it has round rock about 15mm. and its always a 6inch slump or wetter.

its been a struggle to get this stuff to pump. some days a get 30 yards thru then plugs and s-tube is full of pure sand. i traced that back to one mixer truck that had no fins left.

last month, i got 9 yards in and the s-tube was just about plugged solid with half set up concrete. litterally was a hole not large enough to get my fist thru after nine yards! got thru it, then that night adjusted s-tube clearances and the next day same thing.

Sent different truck to the next one same thing.Sent the new truck there and same thing! nobody wants to go back there!

ive tried pumping faster, slower, and dont get me wrong, we will get this project done, BUT if somebody has an idea to make it go better i'd like to know it

most of it is rubber line and pipe jobs, 3.5 inch, sometimes boom with line

oh and we never have any trouble with anyone else's mud!

any ideas?

Ask them for their material batch weights and admixtures and post them here. Must be a secret formula by an uncertified plant :-)

Sounds like its seperating? Maybe some VMA (stabilizer) could help??

I feel sorry for you guys do you have flyash where you are.

Had same problem today, s-tube solid every 30 meters. I talked to the batch man afterwards, says they got 600pounds of cement, no ash, and hot water.

Sounds like a shotcrete mix that's flashing with the hi temp hot water.

Why hot mix ?

What is the rock to sand ratio ?

what kind of sand, maybe reused sand blast material haha. so when my favorite plant lost their access to blend sand i could not pump it so i had to go smaller rock with ash.

I'm not really sure about their sand, or amounts for that matter. I don't really want to complain to them about their mud too much, its a good job. they dont seem to mind the extra time to constantly clean out.

I was just wondering if someone else had much the same thing happen and they changed the way they pumped to help the problem. I got a 350 meter pour out there in a couple weeks. hope it goes better

What kind of pumps are you runing? I know CIFA always has a lot of buildup in the S-tube..

its our job to educate the customer on the requirements of a pump or your peticular unit so when the next guy comes along he will not have to pump trash and wonder what the issues are with someone saving three bucks a yard on the material.

Crazy ...do you watch your pressure guage when pumping this stuff ? Fast or slow, what is the difference ?

You are really not giving helpful info due to your not wanting to rock the boat, by asking questions.Then you will have to be satisfied by being a mushroom, by being in the dark and fed shit :-)