How do concrete mixers work?

These vehicles are vital to construction projects of every scale, but how do they get the job done so quickly and efficiently?

(Image source: Pixabay)

The need for different types of concrete – in bulk quantities – has led to demands for adaptable, variable concrete mixers. The key to successful concrete mixing is to use the correct amounts of each
ingredient. At the heart of the Nurock concrete mixer is a conveyer belt that carries sand and stone, stored in the main hopper, out to a continuous mixing screw. The proportions of sand and stone are controlled using electric flow control gates to vary the proportions. Here, the Nurock mixer lets gravity do some of the work, its hopper’s angled at 45 degrees on the bottom to encourage the material to fl ow effectively. 

The hoppers are even rigged with vibrators to ensure that any blockage is quickly shaken apart. Water stored at the front of the mixer is fed, via a hydraulic pump, into the continuous mixing screw at a specified speed for the type of concrete, all monitored by the Nurock advanced mixer computer system for accountability and accuracy.

Finally, the cement itself is held in a rear hopper. Once added, the completed material is mixed using a
variable speed continuous mixing screw. This produces a uniform flow of freshly mixed concrete from the rear of the mixer, it can be stopped and started at will, with no waste. The mixer can be rotated through 180 degrees and extra delivery chutes can be added allowing up to 20ft discharge from the rear of the mixer allowing the concrete to be placed on the construction site.

Making the mixture

This article was originally published in How It Works issue 15

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