This mix should pump through 80' of 3" line 1720 3/4" rock 1140 sand 640 portland 112 flyash only doing about 30 yards

if its a true 3/4 no larger that 1 inch it should, if its blended with half or some 3/8 would be good. the extra sack of powder will not cover up the the problem if the rock is ugly. the plant should the ability of hose size to the design mix, its their job to know it works. 

haha art that is so true sounds like something that would come out of an escondido plant haha and usually a buck a foot for four inch off the pump and seems if you wet some of the mixes up they tend to push a little easier but if its a four inch mix its not goning to the three inch hose

If I had a dollar for everytime I heard that (the other guy had no problem) .  I found out that the other guy gets whats called a reverse mix,  all sand and a little bit of stone.  I lug around a 4" hose cause our mix lacks the paste and the limestone is 1".  Charge by the foot, huh OK.

 I agree with art. It sounds like an over rock or exposed mix, why so boney? With so little sand that stuff will even bind up in a strait pipe. You may have problems getting it to pump at all. If you try to reduce to 3" I would suggest running 4" to the pour and using 2 or 3 pieces of 3" to place with. So when it wont reduce you wont have to lay out all new system.

 If you have problems getting it to pump at all try turning down the volume with high/full rpm's and it may require alot of on/off on/off to get it to cycle. Low volume+High rpms. That stuff does'nt like to be pushed very hard you gotta coax it along sometimes. Good Luck! 

Its 3/4 minus that the plant uses thanks for the help guys!

Look at the gradation chart for percentage passing of the various screen sizes. If there is a high percentage of aggregates passing the smaller screen sizes it should go through 3". If it's all 3/4+ it is 4" only.

It pumped fine went through 70' 4" line and then reduced to 30' 3" thanks for the info guys. I love this site!!!!!! My 39 meter trailer pump worked fine. Lined it off back end. The day before pumped a 140 yard floor through the boom into 90' of 3" better mix that day they have that one dialed in for 3" line.......