Cement Mixers: How Do They Work? 



Ever ask yourself the question “How do cement mixers work?” If so then you are in luck! This article will not only break it down for you but provide you with almost all the information you would ever need to know about cement mixers, from the most popular types, to how they actually work and so much more. So, continue reading this article if you would like to expand your mind and immerse yourself in the world of cement mixers.


Make Use Of Mixers


The majority of construction equipment is relatively simple to understand. Cranes are used to move things up and down, dump trucks are used to load up, unload, and move out things. One exception to this idea are cement mixers, loved by many children, heavily disliked by in-a-hurry divers, and 965/misunderstood by the majority of individuals outside the world of construction.


Even though concrete has been present in one way or another since before the Romans created the Appian Way, the transport mixer can be seen as the child of the 20th century. Regardless of whether it is a recent invention, the mixer is not going anywhere, it is here to stay.


The first misunderstanding starts with the name. What we refer to as cement mixers are known as concrete mixers in the construction industry and can be found in various sizes, types, and configurations to manage the numerous tasks set for it each day. The need to fill a lot of roles means that this machine is not dynamic, but can change shape and form depending on the needs of the individuals using concrete. For further clarification to understand the difference between concrete and cement let’s use a baking analogue to explain.


The difference between the two is like the difference between a loaf of bread and flour. Concrete can be seen as a generic term referring to a mix of aggregate- typically gravel or stone, cement and water. And contemporary cement refers to a complex mixture of Portland, which is finely ground minerals. Concrete is formed by combining these three ingredients into a mixer, the mixer can either be driving down the road or stationary, the water is then absorbed into the cement, which helps bind the aggregate together, thus creating concrete.




The History Of The Mixer


In 1961, Stephen Stepanian was the first person to develop and patent the first motorised transit mixer. This was done to replace the horse-drawn cement mixers utilised at the time. Horse-drawn concrete mixers had wooden paddles that churned the mixture as the wheels of the cart turned, however, the design could only be used in a limited number of situations.


Unfortunately, it was slow and impractical. A similar could be said about the trucks and engines used in those days. Nevertheless, by the 1940s, the construction of truck frames and engines had caught up to the necessity of having a rugged car that had the capability of lugging thousands of wet, or unset, concrete. After World War II the building boom was in full swing, and mixer trucks were coming into their own.




Interestingly enough, Stepanian’s vision of a better concrete haulier has not changed much from the big drum mixers we see on the road today. Mobile transit mixers are a mix-and-match pick of an engine, rotating mixer, and truck frame. The mixer is comparable, although bigger in scale, to the smaller ones we see at construction sites.


An enormous motor which is separate from the engine spins the drum on the body of the truck, and a cycle of blades, or even a screw is powered by the same motor that keeps the water, cement, and aggregate in a continuous motion. This will keep the premixed concrete from hardening and setting, although time is always ticking to get the mixture to the road, parking lot, or construction site. The majority of cement manufacturers suggest that the maximum amount of time it should take you to mix and ours should be 90 minutes. It would be even better if you can get to the site in less than an hour.


It comes as no surprise that technology has changed over time, and so has the design of the basic mixer. Whilst a lot of transit mixers still have rotating drums, most of them do not just simply pick up a load of wet cement and transport it. The few that do go directly to the sites where the mixture can be poured immediately.


The majority of transit mixers were built with separate water tanks for the truck. The drum keeps the aggregate, cement, and dry ingredients mixing during the trip. Water is only added when the driver is a few kilometres away from the site, this is done to create fresh concrete on delivery.


This is known as “batch” delivery of ready-mixed concrete, manufacturers can mix the ingredients off-site and truck them wherever they need to go. Through the advancement of technology, it has been made possible to mix concrete at the hob location, even though the transit mixers are still located at the workhorse of the specific field.


Metered and volumetric mixers are now becoming the standard. Both of these types of mixers are on-site concrete plants. Different holding tanks of water, cement, and aggregate are kept in one truck that has a computer hooked to pumps and augers. On-site the customer can order the specific concrete they would like mixed into the truck. These mixers are typically utilised during high-rise construction and if need be can be paired with pumper trucks so that concrete can be delivered 15 stories above the ground.




The Past Of Concrete


Elements of concrete like the aggregate, the mix of a binder, and water-has been around since the dynasties of the Egyptian pharaohs when sand, lime, and water were mixed so that it can be used as a mortar in building and constructing parts of the pyramids. They are not the only ones who used a form of concrete in their constructions. Romans were known to use concrete to create the Coliseum, their aqueducts, as well as other important constructions.


In the 1800s scientists started perfecting and experimenting with hydraulic cement, which is what is still used today in the construction industry. The word Portland cement stems from the isle of Portland, just off the coast of England. Here deposits of mineral components utilised in modern concrete were first found and chemically separated. In 1908, a man by the name of Thomas Edison started experimenting with the construction of pre-cast concrete homes in Union, N.J. the majority of these houses are still being used and standing. In 1936, the Hoover and Grand Coulee dams were built and today they are part of the wonders of the world.




Concrete’s Toll On The Mixer


Even though concrete can be found in numerous types, one thing that they all have in common is that concrete is heavy. A big batch can weigh up to 13, 608 kg, this does not include the weight of the truck, which can weigh about 4,536 to 13,608 kg. Only a powerful truck would be able to haul all that weight. The truck must also be tough so that it can load over the rough landscape of the construction site.


Trucks have three different parts; frame, engine, and mixer. The majority of truck companies, fortunately, provide the frame and the engine, with extra add-ons ranging from a computer navigator to a sleeper cab. The volumetric plant or the mixer is then added later on. The reason why companies use a mix-and-match approach to build trucks is that it is aimed at providing a company, who can easily spend between R540 000 to more than R1 800 000, a brand-new truck built to order.


Every single company has their own needs and wants and requires a truck tailored for them. E.g. some people may need a truck with a lighter drum and a heavier engine, which can be removed at any moment and converted into a trash hauler with only a few modifications.




A lot of truck engines range between 250 – 300 horsepower, this depends on the application. Whilst other companies provide engines that have more than 400 horsepower. Horsepower is defined as the measure of power, it’s the engine’s “oomph”. The “oomph” is typically supplied by a diesel engine, usually manufactured by Caterpillar or Cummins.


Diesel engines can make more torques at a much lower engine RPM compared to the gas engine, this makes them ideal for low-speed, and high-power applications similar to hauling or towing. These tanks are preferred as they have longevity- many of them can go for thousands of kilometres or more when they are routinely maintained – also for their roughness.


Diesel engines unlike gas engines work by using compression ignition and need a heavy engine block to be able to withstand the enormous forces that play within them. This compression ignition means that the engine functions at a higher compression ratio inside the cylinders, thus producing more power. This power is then translated into torque or rotational power, via a special gearing in the transferal – mixers can have up to 18 gears and can either be automatic or manual, as well as differentials.


Many concrete trucks can produce up to 3 000 pounds of torque. This means that, in ordinary terms, it is a concrete truck that will probably never beat a street car in a quarter-mile race, however, it can break through the concrete crash barrier at the end of the race without a glitch in the engine RPM and continue going.


Gas engines can make torque at a much higher RPM compared to diesel engines. Any individual who can say that they have towed a trailer or a boat behind a gas-powered vehicle has experienced the urge to press the gas pedal to go up the hill. Diesel engines, due to their design, can make better torque at lower revolutions every minute. So, going slowly on the hill turns out to produce more torque.


About BS Power


There is so much more that can be said on this topic fortunately BS Power is a knowledgeable import and manufacturing company that can provide you with so much information that can ease your mind of any questions you do have about anything related to not only concrete mixers, but construction, forestry, agricultural, and a wide variety of other applications.




We provide products from Honda, Briggs and Stratton, Stihl, Baumax, and Husqvarna. We are based in Cape Town, Western Cape, but have made clients from all over South Africa and even the rest of Southern Africa like; Zimbabwe, Swaziland, Zambia, Botswana etc. extremely happy. We make sure to deliver the best solutions and top-quality equipment like concrete mixers to all our customers.