This type of ready mix concrete plant produces uniform concrete mix through the mixing action of the truck mixer. The mixing action is basically a twofold mechanism. Consider the complex movement of already well mixed plastic concrete in the drum.

At the beginning, neglect the blade action, then rotation of the drum and both concrete internal friction of the concrete and its friction against drum inside surface make the concrete appears to move up the right-hand wall of the drum as shown in Figure-2.

There are two factors which affect the height that the concrete can climb up before gravity surpasses it and make it to fall. Firstly, drum surface linear velocity which based on its angular velocity and the inside diameter of the drum. Concrete falling point is increased with increasing linear velocity. Secondly, concrete workability which its decline leads to rise concrete falling point.

It is observed that, at speed of 22-27 rpm (normal speed is 10-14 rpm), the concrete spins full contact with the drum surface hence concrete falling will no longer exist. This may lead to create problems because substantially efficient local mixing will be lost if concrete falling point is avoided.