For our larger structures, we have been renting a Putzmeister line pump and pumping concrete from our local readymix company. 

However, for AirCrete for this project we wanted to experiment with less expensive to rent pumps. There is no one perfect solution. 

1. https://www.westmarine.com/dometic-12v-t-series-waste-discharge-pump-410878.html  This diaphragm pump is designed for marine sewage applications. It works quite well and is relatively inexpensive for DIY. However, the Gallons per Minute is too slow for larger buildings.

2. The WackerNeuson diaphragm pumps https://www.wackerneuson.com/us/products/pumps/diaphragm-pumps-of-the-pdi-series are high volume, low cost, and perfect.

Of course, you will have to washout all of these pumps with water and make sure to clean between each pour.