Abstract: A pump assembly has a hopper adapted to hold a wet concrete mass and having a front wall formed with a front port centered on a front axis perpendicular to the front wall at the front port and a rear wall formed with two rear ports centered on respective rear axes perpendicular to the rear wall at the rear ports and generally parallel to the front axis. Respective piston pumps secured to the rear wall outside the hopper over the rear ports are operable to draw portions of the mass out of the hopper and expel them back into the hopper through the respective rear ports. An outlet conduit is connected to the front wall outside the hopper over the front port and a distributor pipe in the hopper has a front end fitted and aligned with the front port and a rear end engageable over and alignable with either of the rear ports. A buttress formation fixed on front end of the distributor pipe defines outside the hopper a buttress plane parallel to the front and rear planes.

Abstract: An apparatus for the mixing of building materals includes a cylindrical mixing-container having front and rear sides, provided with mixing tools made up of two carrier arms extending radially outwards from respective front and rear sides, and displaced from each other by 180.degree., two helically-shaped mixing tools supported by respective carrier arms and extending at an angle towards the center of the mixing container and two separately rotatable mixing tools disposed on separate respective shafts ahead of the respective carrier arms.