How to choose a concrete mixer: capacity, motor and drum type

The right concrete mixer depends on how much mix you need per batch and what power supply you have on site. For small domestic jobs a mini mixer with a 120-190 litre drum and a 230 V single-phase motor is enough; for a building site you need models of 250 litres and above, with a three-phase, diesel or petrol motor if there is no mains supply. Always look at the yield, meaning the amount of mix that actually comes out: it is less than the capacity of the drum.

The types

• Traditional concrete mixers. A rotating drum that tilts over to discharge, like the Traditional concrete mixer Mix Officine Polieri. They are the most widely used on building sites.
• Mini mixers and demountable models. Small and light, suited to work at home and on small sites; some can be taken apart for transport, like the Demountable concrete mixer Minihobby Officine Polieri.
• Silenced concrete mixers. Designed to reduce noise, useful on sites close to housing. Towable versions exist, like the Silenced towable concrete mixer BRF.
• Hydraulic reversing-drum concrete mixers. Models for large volumes, even up to 750 litres, like the Hydraulic reversing-drum concrete mixer Unimec FG2; there is also a version with a tilting bowl (FG2C).
• Batching plants (RMC). Plants for producing concrete in quantity, for contractors and large sites.

How to choose by job

The features to look at

• Drum capacity (L). In the collection from about 45 to 250 litres. More litres means fewer batches, but also more weight to move.
• Yield or mix capacity (L). From about 65 to 250 litres: this is the quantity you get after mixing. The data include, for example, 250-litre bowls with a yield of 200.
• Motor. Single-phase electric (230 V) for small jobs, three-phase if you have a suitable socket, diesel or petrol where there is no mains supply. Power is given in HP and kW.
• Weight (kg). From about 50 kg to over a tonne for the large models: it matters for transport and for the ground you set it on.
• Brand and manufacturer. In the collection you will find, among others, Officine Polieri, Unimec and Imer: the product page gives the model, weight and equipment to compare.
• Type of discharge. Manual tilting, with a gearbox or reversing-drum: the more convenient it is, the less effort you make on large batches.

Common mistakes

• Confusing capacity and yield. A 250 L drum does not give you 250 litres of mix: read the yield on the product page.
• Choosing one that is too small. On a real site a mini mixer wastes hours on every pour.
• Ignoring the power supply. A three-phase model needs a suitable socket; if you do not have one, choose single-phase or an engine-driven model.
• Positioning it badly. It must stand level and stable, with the power cable protected.
• Not cleaning it. At the end of the day wash out the drum with water and gravel, otherwise the cement hardens.

Frequently asked questions

What capacity do I need for a small site?

For small jobs a 120-190 litre drum is enough; if you work on site continuously, start from 250 litres.

In what order do I load water, aggregates and cement?

With the drum rotating, first put in some of the water, then the aggregates and cement, and finally the remaining water until you reach the consistency you want.

Can I put my hands in the drum to help?

No. Never put your hands or tools into the drum while it is moving.

Can I leave the concrete mixer exposed to rain?

It is better to cover it and keep the power cable protected; at the end of the day wash it out, otherwise the mix hardens in the drum.

Single-phase or three-phase?

Single-phase if you only have a 230 V socket; three-phase if you have the right supply and work with high volumes.

You will find all the models in the Concrete Mixers collection: to choose the right size and motor, ask for a quote or advice from the AMES technicians.