Concrete - a mixture of aggregates (fine or coarse), cement and water-- is an essential building material widely used in modern-day construction because of its strength, durability and versatility.
Depending on the ratio of its constituent ingredients, concrete can be produced in a wide range of compressive strength or grades.
Typically grades of concrete vary in the range of C5 to C70. M5 grade concrete has a compressive strength of 5 MPa whereas C70 grade concrete has a compressive strength of 70 Mpa.
Concrete of grade C5 to C20 are generally used for applications which don’t require high strength, concrete of grade in between C25 and C45 are used for reinforced concrete applications or construction requiring standard strength and high strength applications use concrete with grade C50 to C70.
These days, concrete is used in the construction of houses, bridges, high rises, canals, roads, tunnels and several other structures.
Traditionally, concrete mixtures were prepared manually which consumed a lot of time as well as lacked precision.
With growing demand and advances in technology, now, concrete mixture, even in small scale applications, is prepared using concrete mixers. Concrete mixers are devices capable of preparing concrete mixtures of varying strength precisely as well as quickly.
Some concrete mixers are even capable of dispensing the concrete mixture directly on the location of the construction.
Depending on the requirement of the application, concrete mixers of various sizes and types are available.
Portable concrete mixers can be used in small and medium-sized applications whereas for large scale applications concrete batching plants can also be built at the construction site.
Concrete mixers can be divided into two broad categories:
1. Batch Mixer
As the name suggests, this type of mixer produces concrete one batch at a time.
Batch mixers either have a drum or a pan, consisting of blades, which when rotated prepares the concrete mix.
The speed of rotation, angle of the blades and in some cases the angle of inclination of the drum can be controlled.
These are the most commonly used concrete mixers and are highly preferable to be used in small and medium-sized construction sites.
Batch mixers can be further divided into two types:
i) Drum Mixer
These mixers consist of a double conical frustum shaped drum.
Depending on its type, the drum either has a single set of blade or multiple sets of blades which are used to mix, prepare and discharge the concrete mixture.
ii) Pan Mixer
This type of mixer has a cylindrical pan instead of a drum in which concrete is prepared.
Just like drum mixers, these mixers also have blades which facilitate the process of mixing.
These blades are generally shaped like a star to ensure optimum efficiency.
They also have scrapers attached to avoid sticking of mortar to the surface of the pan.
Commonly used pan mixers have two different modes of operation:
First, there are pan mixers in which the pan is fixed and the blades rotate in a vertical axis.
Second, in some pan mixers, the blades are static while the pan rotates in a vertical axis.
Pan mixers are considered to be the most efficient type of concrete mixers.
o matter how the mixer operates, both types of mixers are equally efficient.
The concrete mix is generally collected from an opening at the bottom of the pan.
These mixers are most suitable for preparing stiff and lean concrete mixes.
2. Continuous Mixer
These concrete mixers work without any interruption and keep producing concrete continuously as long as work is going on.
They are fed raw materials continuously and the concrete is discharged and collected by construction workers as soon as the mix is ready.
Continuous mixer systems are generally set up in the construction site itself.
They have a separate feeder unit for the intake of constituent materials, a mixer unit for mixing concrete and a discharge mechanism for dispensing the concrete mix.
These mixers are deployed while constructing very large structures such as bridges, tunnels for roads, dams, etc.
Suitable for field mixes of low/medium strength concrete.
Drum volume: 130 litres
Yield: 75 litres of concrete
Power supply: 230V 1ph 50-60Hz - 0.3HP
Dimensions: 720x1320x1280 mm
Weight: 60 kg approx.