Truck
Concrete mixers have a turning drum on back. Turning it one way mixes the concrete. Turning it the other way pushes the concrete out. The concrete goes down "chutes" (like large pipes with an open top). On most trucks the concrete comes out the back. Some new types have the concrete goes over the cab and down chutes in the front. Concrete is very heavy and hard to mix. Concrete mixers have to be very heavy duty.