Is it cement truck or cement mixer?

Normally about 1-2 meters each. Most trucks have 2 on the back and 2 stored somewhere else on the truck.

Actually, the rotation is mainly to keep the concrete well mixed and homogeneous during transport, thereby insuring the sand, gravel, water, and cement is well mixed. The concrete itself will set up...

8 or 9 yards, depending on the company's policies and their location laws.

Silica flour and Silica sand our admixtures to Portland cements.

About 8m^3