Concrete is the most widely used building material. When cement paste fills the gaps in the coarse aggregate with sand, and the resulting mortar fills the voids, the concrete is the densest and strongest. The cement should cover every single grain of sand. Before the mixer machine concrete was created, the entire mixing procedure was carried out by hand, using a shallow box and a shovel. However, numerous types of mechanical processes and machinery are being used for mixing because of the increased demand in the construction industry.
See also: Concrete calculator: A guide to using a concrete calculator
What is a concrete mixer machine?
A concrete mixer is a device that mixes cement, aggregate (sand or gravel), admixtures, and water uniformly. Drums for mixing, feeding, unloading, water supply, a prime mover, and transmission mechanisms make up the machine setup. The apparatus essentially encourages particle collisions and the growth of dispersion. This machine typically consists of three main units: a feeding unit, a mixing unit, and a discharge unit.
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Types of concrete mixer machines
There are following types of concrete mixers.
Continuous concrete mixer
In continuous mixers, components are continuously added and then released in a steady stream. Screw feeders load materials constantly.
Features
- Compared to the batch mixer, productivity is higher.
- It is challenging to regulate the material percentage and mixing time. In a longer mixing drum, the feeding, blending, and discharge procedures continue repeatedly.
Self-loading concrete mixer
Self-loading mixers can dispense and move concrete on-site autonomously.
Features
- Effective since they can load them themselves (no further equipment required!).
- Helpful for construction that is both narrow and compact.
- Low tyre pressure, large tyres, and swinging rear axles (provides good off-road performance), an electronic weighing system, motor, and hydraulic system.
- Consists of a revolving drum fixed to a chassis frame positioned in the operator’s cab and equipped with a loading bucket.
- The optimum locations for this kind of mixer are those without access to concrete batching plants.
Compulsory concrete mixer
The mixing device, reducer, shaft-end sealing, electric lubricating oil pump, and discharge system are all components of a twin-shaft compulsory mixer.
Features
- At both ends, axes are fitted with a floating oil sealing ring.
- Completely automated system.
- Eccentric hopper gate double seal design.
Rotary or non-tilting type concrete mixer
Rotating the drum along its horizontal axis is the only permitted method of discharge for rotary mixers.
Features
- The drum has two openings at either end, one for pouring and one for discharge.
- As a result of the inability to discharge quickly, concrete can occasionally segregate.
Tilting type mixer
The tilting type mixer is a mixer with a spinning drum to dispense the concrete.
Features
- Mixes the materials while rotating ahead and quickly discharges the mixture downward using gravity.
- Used to mix semi-dry concrete with plastic.
- Reduced noise, reliable performance, and easy mobility.
- The form, angle, size, and angle of the blades all affect how well the mixture is mixed.
Forced concrete mixers
For hard concrete, lightweight aggregate, and liquid concrete, forced mixers are specifically designed. This is specifically utilised in the batching plant for concrete. The device is specifically made to continuously and uniformly combine gravel and resin.
Features
- Have the spindle arms fitted with stirring blades
- There are two categories of disc vertical axis forced mixers: Planetary and turboprop type.
Self-propelled concrete mixers
Features
- Have vertically positioned stirring blades on the interior wall of the mixing drum.
- When materials that have been put into the drum are elevated and then dropped by gravity, the drum rotates horizontally.
Vertical shaft mixer
Features
- It is used in high-performance concrete as well as conventional or precast concrete.
- Includes the frame, the stirring cover, the follow-up paddle, the cylinder, the lifting slider mechanism, the electric component, etc.
- Concrete is mixed in a circular pan that has blades arranged in a star pattern inside of it.
Horizontal shaft mixer
Features
- The horizontal design of the paddle mixer makes it simple to mix a variety of aggregates, especially the larger ones, to produce a more homogenous slurry.
- Ideally suited for dry hard concrete that is lightweight.
Drum mixers
Drum-type mixers are a specialised type of equipment used in the concrete industry to mix various ingredients and create high-quality concrete blends. These mixers have a distinctive double conical frustum shape, resembling a drum, which contributes to their efficient mixing capabilities.
Features
- Depending on the specific type of drum mixer, it can feature either a single set of blades or multiple sets of blades. These blades play a crucial role in effectively mixing, preparing, and ultimately discharging the concrete mixture.
- Drum mixers are available in a wide range of configurations, each catering to diverse needs and applications.
- Drum mixers utilise a unique paddle design known as the swing-blade paddle. This design incorporates multiple blades curving in different directions.
- The swing-blade paddle optimises the movement of liquids within the rotating drum, significantly reducing the time required for thorough mixing.
Pan mixers
Pan mixers present a distinctive approach to concrete mixing, featuring a cylindrical pan as the central mixing element. This innovative design enhances the efficiency and quality of concrete preparation for a variety of construction projects.
Features
- Similar to drum mixers, pan mixers are equipped with blades that facilitate the mixing process. These blades are strategically shaped like stars, ensuring optimal efficiency in blending concrete ingredients.
- Inside the cylindrical pan, concrete is expertly mixed using a series of star-shaped blade arrangements. This advanced mechanism guarantees thorough mixing, resulting in a well-combined and homogeneous mixture.
- Pan mixers are designed as erect rotating shaft concrete mixers, making them ideal for achieving intricate and complex mixes. This design ensures that even the most challenging mixtures are completely combined, maintaining a consistent and robust momentum throughout the mixing process.
- These mixers are available in various sizes to suit different project scales. From small-scale applications to large industrial projects, pan mixers can handle substantial quantities of concrete. Some industrial-grade models can even hold up to 1000 gallons of material.
- To prevent mortar from sticking to the pan’s surface, pan mixers are equipped with scrapers. These scrapers play a crucial role in ensuring that the mixed concrete is efficiently discharged without any wastage or residue.
Reversing drum mixers
Reversing drum mixers are a specialised type of concrete mixer renowned for their ability to produce concrete in single, well-defined batches.
Features
- The distinctive feature of reversing drum mixers is their entire drum that rotates around its axis. This rotation mechanism plays a crucial role in achieving uniform mixing.
- Materials are loaded into the drum through a charge chute located at one end, while the mixed concrete is discharged through a separate discharge chute at the opposite end.
- Reversing drum mixers offer versatility in loading and unloading options. In some models, materials can be manually loaded into the drum through charge chutes. For added convenience, newer models feature self-loading capabilities.
- The essence of reversing drum mixers lies in their rotation reversal mechanism. This innovative approach allows for various actions during the mixing process.
Twin shaft mixers
Twin shaft mixers are a powerhouse solution tailored for industries that demand substantial quantities of top-notch concrete output.
Features
- The defining feature of twin shaft mixers is their utilisation of two robust counter-rotating shafts. This design element contributes to a rapid and thorough mixing process.
- The simultaneous counter rotation of the twin shafts results in a swift and dynamic mixing action. This rapid blending not only enhances the quality of the concrete but also expedites the overall mixing process.
- Twin shaft mixers can effectively manage mixtures containing coarse aggregates with diameters of up to six inches.
- The capabilities of twin shaft mixers extend beyond traditional concrete production. They are equally adept at handling tasks such as asphalt mixing, glass batch preparation, and even the production of sand-lime bricks.
- Twin shaft mixing unfolds over three distinct phases. It commences with the amalgamation of materials, followed by the intensive mixing phase and concludes with the efficient discharge of the perfectly blended mixture.
FAQs
How long can concrete be allowed to sit in a mixer?
Concrete from a truck mixer or agitator truck at a central or mobile ready-mix plant needs to be discharged within two hours. This duration is shortened to one hour if non-agitating transportation machinery is used.
How long should the concrete be mixed inside the machine mixer?
To avoid cold joints, you have about an hour from the time you start mixing to mix and arrange all of your elements. You may finish up to 12 rounds of mixing in that amount of time, with each cycle taking roughly 5 minutes.
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