Concrete mixers, also referred as cement mixers, are used to transport and combine cement, aggregate and water to form concrete for workers to use at construction sites. The dry materials and water could be loaded in the machine and get mixed during the transport. Or they could be already mixed before loaded in the mixer.
The motor of concrete mixers rotates the drum on the truck body and powers blades and a screw to constantly mix the cement, aggregate and water, keeping the premixed materials in a liquid condition. The drum’s interior is equipped with a spiral blade. In one rotational direction, the concrete is forced deeper into the drum until the concrete mixing transport trucks arrive at the construction sites. This is the process of charging the mixer. In the other direction-discharging the mixer-the concrete is pushed out of the drum and goes on chutes, into concrete pumps or on conveyor belts.
Most concrete mixers nowadays also have a separate water tank. The spinning drum keeps mixing the dry ingredients, aggregate and cement during the transport. And within a few miles of the construction sites, water is added from the water tank to create viscous concrete.
There are also requirements about location of the construction sites. It’s suggested that the time between mixing and pouring should be controlled within 90 minutes because the concrete starts to set the moment it is loaded in the concrete mixers. If the concrete hardens caused by the truck breakdown or other reasons, workers may have to enter the barrel with jackhammers. Therefore, it’s better that the truck could get the concrete to the site within one hour.