I am going to be pumping scc into columns at  an existing building and need to know if there is anything out of the ordinary I need to be aware of. I made a search on scc and read about it but did not mention much about pumping it. Any input would be appreciated.

Mix designs for scc probably vary from region to region, but here is my experience.

Check with the RM plant to make sure they have a PUMPABLE scc design on file.  This usually involves adding lots of flyash or slag, since scc has a very low cement content.  I pumped it with flyash, stopped between loads and started up again no problem. 

 If they do not have flyash that is a different story.  It may pump, but it will have to be super wet (usually is anyway because that is what makes it compact) and you can't stop.  Otherwise the water will bleed from the sand and you will have a boom full of sand.  Timing with the RM plant is important in this case.  I also had a dim mixer driver fill my hopper with a 3inch slump, and that brought things to a grinding halt as well. 

Hope this helps.

Hmmmm !  After I wrote the reply I realized I might be talking about flowable fill not scc. Checked it out on google and scc is something else. Looks like they are talking about superplasticized concrete that doesn't need vibrating. The reason I made this mistake is because a customer of mine always always called flowable fill scc.

 I have pumped this stuff too.  It was easy to pump because it was high in cement content and runny. But the plasticizer will wear off quickly and it will set up fast.  Probably not a good idea to let it sit too long in your boom.

keep it moving. once you stop, the sand settles and you'll sand plug

SCC is smooth to pump, but it depends on the mix.

Our customers, and we pumpers, prefer small gravel or pea gravel, since with bigger or crushed, flakey or anything not very consisten roundish there is alot more surface area to spread the cement paste on, wich is your lube in this semi-separated mud, so you could get segregation of the worst kind.

And dependig on the mix, it is sometimes advisable to not run your agitator, and in any case, if you are waiting any lenght, shut down and turn of the engine, the vibratitions will separate the mud in the hoppper and in worst case, pipes.

You do not need water to prime with because the mix is super wet and you cant even see the rock in it. I have pumped it a few times. Once we sat for 20 minutes because the wall blew out. Started back up no problem. Just be careful with it. It sets up fairly quick, just like pumping straight sack mix.

thank you all for your advise. I am planning on doing more research because of the need to know. If any of you think of anything else please throw me a message.

Todd if you read this, thanks for the site, very helpful and where else can a pumper get advise from other pumpers but here.

If you are concerned at all, see if you can get the plant to batch 3 yards so you can do a test.  (less than 3 yards doesn't mix well)  Have them mix for at least 10 minues before conducting the test.  Make sure all the specs are met before starting.  (Air, slump/spread, etc....)  Have the truck back up to to you, and you can a-frame and prime back into the mixer.   (keep people clear)   Pump slow, then faster, stop/start.  Wait 2 min, 5 min, 10 min, etc.  See how the mix reacts to pumping under pressure (A-framing should give a good idea)  Perhaps you could stretch it flat out to pump into another mixer and test it during a wait like that too.  Or flat-out to a waste area if they can't use it in another load (non-spec) that they could top up.  Just my 2 cents worth.

I pump SCC all the time, it pumps just fine for me in my schwing. In agree with the others, dont let it sit to long as it will begin to seperate.

flowfill I did a mix design with 400 lbs cementuous material that pumps great , went down to 50 lbs of cement 350 flyash and pumped fine has to be wet and air content needs to be above 5%, shouldnt have any problems.

 Ive pumped it alot. Everything everybody said is true, just keep a eye on it. One pour I had with it a form saver broke 5 floors up, and every time I walked by the core wall I thought I was in the mountains walking by a waterfall, it sounded so pretty.