Merlo vs Carmix

In this article we will compare Carmix and Merlo mobile batching plants.

What is a self-loading concrete mixer?

Firstly we need to introduce the concept of a self loading concrete mixer. This type of equipment is not common in the USA special-purpose machinery market. It is often confused with volumetric mixers and conventional concrete trucks. That’s why we think it’s important to define this type of special equipment.

Self-loading concrete mixer is a mobile batching plant that automates the entire process of concrete production from loading of materials to moving around and discharging the mortar on site.

When a certain type of special-purpose machinery becomes popular on the market, many manufacturers start producing it. The same happened with concrete mixers. A number of European companies supply similar special-purpose machinery around the world. What are their main differences?

Let’s start the comparison!


Carmix (Metalgalante) and Merlo are both manufacturers of self-loading concrete mixers located in Italy. This type of equipment appeared on the market in the 60`s. Manufacturers keep up with technology and continue to improve concrete machinery.

Merlo is a diversified manufacturer. The company offers a wide range of choices from front and swinging telescopic loaders to tractor-manipulators. This list also includes two concrete mixer models with self-loading.

Carmix was originally designed for concrete production. Manufacturer is only involved in the concrete construction sector. For this reason all engineering departments focus on the development of self-loading concrete mixers and additional equipment like concrete pumps, bulk bags and storage hoppers.

Carmix takes into account the individual conditions of different construction sites. That is why there are 8 different models of concrete mixers with different technical features. They vary in terms of mixing drum capacity, loading type, integrated functions and cab design.

A wide range of concrete mixers produced and sold by Carmix allows you to choose the most suitable model for your specific needs.

To demonstrate differences and similarities of Carmix and Merlo, we will compare two most popular models: Carmix 3500 TC and Merlo DBM 3500 which have similar outputs and dimensions parameters.

CharacteristicsCarmix 3500TCMerlo DBM 3500
Output4.5 yd³ per cycle4,5 yd³ per cycle
Mixing drum capacity1281 gallons1320 gallons
Height10,4 feet13 feet
Length18,5 feet18 feet
Width8 feet7.6 feet

Operator’s cab position

Presented concrete mixers have a significant difference – the height.

DBM 3500 is 20 inches taller because of operator’s cab position. If you compare Merlo and Carmix cabins, you can see that the Merlo cab is located higher up. This design decision was made because the engine and internal systems of the machine are located at the front of the mixer.

Some of the components of concrete production machinery are under the seat, so the cab is positioned higher. Engine under the cab may not be the best engineering solution.

As self loading concrete mixers are meant for long and continuous operations, the engine gets really hot and the metal body passes the engine heat into the operator’s cab. This can become a real problem during the hot summer operations.

Parameters of the cabin also affect the maneuverability of the concrete mixer. Special-purpose machinery will not be able to pass inside some premises because of the height. To demonstrate this issue just consider pouring inside a building or a hangar where the entrance is limited in terms of height.

However, high position of the cabin can also be advantageous.
Operator has a wider view of material loading. This is important for Merlo concrete mixer because the bucket and all the loading mechanisms are located on the other side of the machine from the cabin which makes it tricky for precise loading. Initially, operator can not follow the loading process because of concrete production machinery structure.

Operator has 3 rear-view mirrors to compensate for the poor visibility due to rear loading type. However, it is difficult to use because you always need to look out of the cabin, bend your head every time to see what is being loaded or discharged. This fact can have a negative impact on operator’s health later.

Carmix 3500 TC has a lower cabin position than DBM 3500, but this is not a disadvantage. Operator has a full view of the construction site with an all-round glazed cab. Bucket of the mixer is next to the cab and loading takes place in front of the operator’s eyes.

Technical characteristics

In the table below you can find that сoncrete mixers have slight modifications in the technical field:

CharacteristicsCarmix 3500TCMerlo DBM 3500
EnginePerkins 1104 TA C-44(Tier 4) Deutz (Stage IV – T4)
Operator’s cabFixed seat, one control panel
Swivel seat, two control panels
Weighting systemStrain-measuringStrain-measuring (optional)
Engine power (kW/hp)84/11474,4/100
TransmissionHydrostatic, four-wheel drive. All four wheels are swivelHydrostatic, four-wheel drive. All four wheels are swivel
Speedup to 25 mphup to 25 mph
Concrete discharge angle300°300°
Dispensing bucket158 gallons184 gallons
Water tanks (total volume)211 gallons245 gallons

Concrete mixers components from two different manufacturers are known for their reliability and quality.

Perkins is a British diesel engine company, and Deutz is German.
These engine manufactures are well-known in the field of concrete production machinery. Their engines are ideally suited for heavy and prolonged use. You should notice that DBM 3500 is equipped with a Perkins engine.

Difference of more than 10 horsepower may not seem significant., however, it can become noticeable with years of use. Engine power will begin to decrease after years of continuous use. A concrete mixer with more horsepower will perform better than one with less power.

Integrated water tanks of Merlo are larger than Carmix.

Water tank capacity of Carmix 3500 TC is based on the amount of water needed for one concrete mixing cycle (about 166 gallons). The remaining water is aimed for one equipment cleaning with the help of a high-pressure washer.

Therefore, you do not have to waste time at the end of the shift and drain the excess water from the tanks. Compared to Merlo tanks, which are larger, you need to discharge water or leave it until the next shift.The last point can have consequences, because if it is cold outside, water can freeze in the tank and damage pipes.

These minor differences do not have a significant effect on operation, speed and quality of mixture production.

Main differences are in functionality and design solutions of manufacturers.

Both mixers have an electronic aggregates weighing system. However, this system is included as a standard feature in Carmix 3500 TC. Strain gauges are mounted underneath the mixing drum, they read the data and transmit to the onboard computer in the operator’s cabin.

Merlo also has a weighing system, but it is installed on an individual request and is an optional equipment. You can find this information on the manufacturer’s website.

Control board

Merlo makes everything for comfortable and convenient operation of concrete mixer. DBM 3500 has two control boards inside and outside the cab and two steering circuits inside.

You may ask “Why do they need so many cabs?” – We will explain.

Concrete mixer has a 180° seat swivel function so that operator can turn on the mixing drum and watch the loading and discharging. Engineers decided to integrate another steering circuit behind the operator’s back so they wouldn’t have to move it. It’s an advantage to keeping an eye on the concrete production process. Operator doesn’t need to be constantly distracted in order to control the operation process.

Control board behind the operator’s back seems like a reckless decision. There is no denying the human factor. Operator works for 8 hours and monitors every stage of concrete production. He can forget about the control board behind and accidentally hit one of levers.

Carmix 3500 TC does not have a seat that rotates 180 degrees, because operator has a perfect view of the loading and discharging process. Three Carmix models have this feature: the ONE, 25FX and 45FX. They are designed for work with cramped conditions, where it is difficult to turn around.

These mobile concrete mixers have not only a pivoting seat, but also an entire steering circuit. There is no extra board behind operator, because all control elements swivel with the seat. This way, the manufacturer avoids potentially dangerous situations for the operator and everyone on construction site.

Merlo concrete mixer has one more control board for discharge process, which is located next to the mixing drum outside the cab.

It’s convenient to use when an operator needs to discharge concrete into a small pour area and keep track of the volume of mix being discharged. Control board is covered by a removable metal enclosure that protects levers from concrete spillage.

Installed metal enclosure helps only when cab is not used for operating.
When the control board is fully open, it is easy for concrete spatter to get on it. Because mortars harden quickly and control board can easily fail due to concrete buildup.

A portable control unit compensates poor visibility from the cab if discharging takes place on site that obscures the mixing drum. Operator has to get out every time, and put a mobile concrete mixer on handbrake.

Let’s consider a situation: mixer drives up and misses the pouring area. If the area is filled and mixer needs to place concrete about 6 ft away from this one, operator would again get back into the cab, drive that distance and get out.

Unnecessary operators’ action wastes a lot of time that could have been spent concreting the site.

Such disadvantages can only occur in the perspective of operating DBM 3500.

Carmix 3500 TС has only one control board in cab. Design of the machine allows operator to stay in the cab and move around the site, load components of mixture and discharge finished concrete. This saves operator’s time, thus speeding up the concreting process.

Operator training

Here we are going to talk about the duration of operator training. It’s easy to operate this kind of concrete production machinery.

All depends on how many functions operator needs to memorize before starting to mix concrete.

No matter how mobile concrete mixer is multifunctional, it will still be operated by a human. Therefore, ergonomics and ease of operation plays a major role.

It is easy to learn how to operate Carmix. As stated above, if you know how to operate excavators or loaders, you can easily control a concrete mixer.

It usually takes a new operator just a couple of hours to familiarize himself with all the operation nuances of Carmix and produce his first batch of concrete.

Merlo mobile batching plants have multiple control boards, which can be difficult to get to grips with operating. It takes more time to clarify and learn this equipment.

Operator has to spend a lot of time not so much on studying each of the boards (they are similar in functionality), as on remembering the sequence in which to use them.

For this reason it will take an operator longer to learn how to operate Merlo compared to Carmix because of the large number of single-type functions.


We mentioned above the differences in bucket position between DBM 3500 and Carmix 3500 TC. Operator does not have the same visibility in Merlo compared to Carmix because of the rear loading type. Even if this disadvantage is compensated by the portable control unit and the height of cab.

There is a difference in volume between buckets of the two mixers

CharacteristicsCarmix 3500TCMerlo DBM 3500
Dispensing bucket158 gallons184 gallons

Merlo bucket is wider and larger than Carmix. DBM 3500 can load the mixing drum 16,5% faster, as you can see from characteristics.

Carmix has a narrower bucket that is elongated in length. Based on our experience, this kind of shape is better for fine finders.

Let’s consider cement as an example, if there is a lot of space in a bucket, tiny flakes of cement start flying in the air. When a light wind gets into it, material will fly away without entering the mixing drum.

Two concrete mixer models from different manufacturers Merlo and Carmix are similar in several ways. They have quality components, the same performance and similar technical characteristics.

However, there are significant functional differences in each of mobile batching plants, which have an impact on the entire process of concreting.

For example, a more ergonomic and simple functionality, which is not loaded with additional control boards can at times speed up operator’s work and concrete production. Different loading types (rear loading for DBM 3500, front loading for Carmix 3500) also affects the speed of concrete production, safety and ease of operation.