Concrete mixers blend cement, aggregates, and water to produce concrete. To get the proper concrete mix, the concrete uniformity must be maintained and the workability of the concrete must remain intact. there are various types of concrete mixers available, which quickly produce a better quality of concrete at an economical price.
Types of Concrete Mixers
There are two main types of concrete mixers used in the construction industry.
- Continuous Mixers
- Batch Mixers
1. Continuous Mixers
Continuous mixers are suitable for large-scale projects such as dams, bridges, skyscrapers. Because there is a large quantity of concrete is required at fast-paced and the quality of concrete must be maintained. Therefore, continuous mixers are installed at such construction sites.
The continuous mixer is a type of concrete mixer that loads the raw ingredients through screw feeders, blends them, and discharges concrete until the work is completed or a work break that contains large-sized aggregates occurs at the construction site.
In a continuous mixing plant, the machine is taking care of batching, mixing, and adding water according to the concrete mix design. Once the mixture is created, it can be transported into any designated location, through a concrete pump, as well as through a wheelbarrow or bucket.
Continuous mixers allow faster casting of concrete because it reduces the wait time as compared to manual batching. The incorporation of AI technology makes it easier, by combining
Some approaches such as “ just add water and set and forget” mixes will be more consistent and high quality. continuous mixers are the types of concrete mixers that are more expensive to operate and maintain.
2. Batch Mixers
Batch mixers are commonly used concrete mixers on small-scale and dynamic projects. As compared to continuous mixers, batch mixers are small, moveable, and mix concrete by batch and discharge into wheelbarrow or concrete lift to carry.
Once the cement, sand, and coarse aggregates are poured into the drum along with water according to the specified mixed design. The drums rotate for some time at a fixed speed. There are steel blades in the drum which helps in blending the ingredients properly. The resulted concrete load is discharged and another batch is filled. the whole process is repeated until the work is completed or the required quantity of concrete is poured in. batch mixers are the most useable types of concrete mixers, there are two types of batch mixers.
- Drum Types Mixers
- Pan Type Mixers
1. Drum Types Mixers
Drum type mixers are blend concrete ingredients in a double conical shape drum. Drum type mixers are further classified into three types.
- Tilting drum mixers
- Non-tilting drum mixers
- Reversing drum mixers
Tilting Drum Mixers
Tilting drum mixer discharges concrete by tilting downwards. It uses a quick mixing and discharge process and is used on large-scale projects. The tilting drum can be inclined at various angles. Tilting drum mixer delivers concrete by gravity that is tilting the drum downwards, because of this the concrete obtained will be not segregated. Aggregates greater than 7.5 cm can also be mixed efficiently by tilting type mixers for low workability concretes. There are few factors that affect the mixing efficiency of concrete as follows.
- The shape of the drum
- The angle of the drum
- Size of blades
- Angle of blades
The tilting mixer has a disadvantage in that sometimes concrete sticking to the bottom of the drum. To solve this problem, buttering of tilting mixer is necessary, buttering is a process of applying some amount of cement mortar is mixed in the mixer before the first batch of concrete.
Non-Tilting Drum Mixer
Non- tilting drum mixers are not allowed to tilt and the drum rotates about its horizontal axis. For the discharge of concrete, a chute is arranged in an inclined position which will receive the concrete mix from the drum and discharges it out. the drum can be opened from two ends and consists of blades inside the drum, concrete ingredients are poured through one end and the mixed concrete is collected through another end. Fast discharge of concrete is not possible in this case. Because of this delay, there is a high risk of concrete segregation.
Nontilting drum mixer is not suitable for bigger aggregates of 7.5 cm as they will not discharge from the drum easily. It is suitable for small projects where less efficiency is accepted.
Reversing Drum Mixers
The reversing drum mixers work similar to the non-tilting mixers but the drum has only one opening. The same opening is used for filling the drum with concrete and discharge the concrete mix by reverse rotating. A prime example of reversing drum mixers is a concrete mixer truck. Which is more commonly used on construction projects these days.
The drum rotates in one direction with the help of a powerful motor, this mixes the concrete ingredients, to discharge the concrete, the drum rotates in the opposite direction. There are two sets of blades installed on the inner walls of the drum. One blade pushes the concrete upward to the center of the drum and the other blade discharges the concrete when the drum rotates in the opposite direction. the blades are installed in such sequence that they can discharge the concrete mix without the danger of segregation.
Reversing drum mixers are commonly used mixers to produce medium to high-quality concrete for residential and commercial buildings in a very quick time. Their operation and maintenance cost is also very low as compare to the other mixers. These types of concrete mixers are mainly used in developed markets to speed up production and delivery at competitive prices.
Pan Type Concrete Mixers
For the pan types of concrete mixers, we use a circular pan to mix the concrete. The concrete mixing is done by steel blades, which are installed in star shape inside the pan. There are two types of pan mixers.
In Type one of the pan type concrete mixer, the circular pan is static and the star blades rotate on the vertical axis of the pan. In the second type, the circular pan is rotating and the blades are in a static position. by using pan type mixer.
The mixing is efficient and the concrete mixture is discharged from a central hole in the pan. The rotating star blades are called scraper blades and don’t let the concrete stick to the pan. The blades are adjustable in height as well, and there is no space to keep the mixed concrete. which that the mixed concrete must be used quickly. We can say among all types of batch mixers pan type mixers are more efficient and economical.
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