I've had a customer ask about pumping lightweight.   It's a fairly big job, a few different pours....   I run a Schwing 750 18X with 2 1/2 inch line.   Is it possible to pump this?   I know the aggregate should be saturated, but getting it through 2 1/2 inch line?   Any help or suggestions will be greatly appreciated. 

any real bad day I had pumping involved the word lightweight!

I pumped through 3" once . Still didn't enjoy the experience. There are so many things that are out of your control and if they aren't done just right it becomes your fault. Book something else or go fishing.

It all depends where you are at.... In the S.F. north bay area we have mixes with material fines so sweet that we can push lightweight mix through 2 1/2" line as long as the slump is between 4 and 6. Any dryier, and it wont flow and any wetter, it wants to seperate. VMA is the magic potion additive for any mix. ask your ready mix supplier for VMA or V-MAR, Gods gift to concrete pumping.

No way. Who's buying if it doesn't pump? you'll know on the first half yard. maybe a test pump.

If you have never seen it before , it looks like rocks with sand and cement running under it , coming down the chute. With one company in Delaware it goes through our squeeze pump well , with others we have problems . Very specific mix to be able to pump . I just had a forty yard pour last week from a plant I don't usually work with ,  had to throw the first truck away after two hours of trying and many jams. 2 3 4 truck went through no problem , which brings it all back to it ends up  being out of your hands , if they don't soak the stone all night you can forget about pumping it !the plant it came from told the customer it was a problem with the pump  ,which it obviously wasn't but it is still bs to have to explain yourself and why you had to reject a load because of their f/u

What kind of light weight? Is it something called ''starlight'' ? Vulcanic rock.. We are going to pump that on our bridge here in Norway. Might be up to 500m line. But of course we use 5'' system.

2 things are very important.

Don't pump to fast. Give the concrete time to fill your cylinders. If you pump to fast you will suck the juice out of the concrete and you will end up with a hopper full of rock.. Slump needs to be quite high.

Don't use to much pressure and keep an eye on your meters.. When you raise the pressure but the volume output don't go up you know you have reached the max speed for that concrete. Better to than lower the pressure a bit. You will only destroy the concrete by pushing harder. (not sure if your pump shows how much m3/h you are pumping?)

How long is the line?   

just pumped lightweight through a schwing sp 500. my experience is big line, little or no reduction, low pressures, 6-8 slump going into pump mid-range water reducers, air, and as little rubber hose as possible. i'll try to snap some photos of the next lightweight pump set up for you. I put it through 100' of 3'' slick line and 125' of 3'' rubber. my pressures were around 1300psi., i had no trouble. the agg. is usually small enough to theroetically go through a 2.5'' system, but i would not even chance it. the reduction and increased pressure is a recipe for diaster. most recommend a 4-5'' system for placement.

I pumped the volcano looking rocks once through a 2.5" hose 200' long.  Started out at a 9" slump and at the end was a 4.  We did pump slow because of pouring a set of steps.  Went well.  Took a double handfull of mud and dropped into a 5 gallon bucket of water.  Quite a few rocks floated and that is scary.