I have pump balice crete into ships and did some test pumping of steel shot and zinc you have to wach how you place the boom some of the test where to find the tip faxter and see how close it was to the enginers theray

how dence is a cubic foot to standerd concrete

Art,are we talking for radiation shielding?

If so,that question came about a long time ago (25+) at that time we were adised to keep out of boom (breakage).However I know they did some here within the last 10 using the 1st and second section.

Art,

I checked a couple of my mixes for weight. They are all around 143 lbs/ft³ plastic. Did you tell me your mix was 140lbs?

we found that you relate the weight of the mix to your standard mix then to the length of boom ie 50% heavier then use max half the boom . check with your contractor and the safety person. We checked beforehand with the pump dealer and also the client (UKAEA) and all was agreed on our contract. One point to remember is that the mix/aggregate is usually 3 times the price of ordinary and the formwork is that much more critical  so a source of back up is essential. 

 If unsure though, use a ground line!!

art 

You are talking about 'slag' aren't you?

The boyz in Memphis, TN know about that stuff. One of them could probably help you.

art

the ag size and grad of fines is going to tell you if it will pump just remeber that when you stop all that wieght will compress so back pump 1 or 2 strokes when you stop and when you start strok it 1 more back then forward this is what we had to do for a zinc based mix and it was about 180ish per cf

The aggregate they use over here comes from sweden, looks like granite chippings in the hand . The mixes are usually the stronger mixes  and therefore contain more cement and maybe a percentage of slag (depending on what you are pouring) which make them better to pump, but on the down side the mix is stickier and will require a bit more pressure on the pump.