The concrete mix must be batch-mixed, transported, placed, compacted, and cured to attain the appropriate characteristics and strength. Ensuring the finished product satisfies the project's criteria is a complicated and crucial procedure requiring careful attention to detail and quality control.
The concrete manufacturing process involves several stages: batching, mixing, transporting, placing, compacting, and curing. Manufacturing concrete has several benefits, including versatility, durability, sustainability and low maintenance.
In this article, these steps are involved in producing the concrete process and the best method for transporting concrete in case of mass concreting.
Since the time when limestone was crushed and burned to make concrete, the process has advanced significantly. Early civilisations used a simple mixture of crushed stone, sand, and water to create the craft, which has since developed into a sophisticated industry.
Modern structures and roads are made of compounds produced using sophisticated chemistry.
Did you know?
India produces 500 million tonnes of cement each year, making it the second-largest cement producer in the world.
What Is a Concrete?
Different varieties of concrete exist, from plain to reinforced concrete with embedded steel bars and rods. This is a result of the development of the modern concrete industry. Although innovation has enabled humankind to create magnificent structures, many long-standing safety issues and worries continue to exist.
High-quality concrete is a homogeneous blend of cement, coarse and fine aggregates, and water that hardens into a mass due to a chemical reaction between cement and water. Each of the four components serves a distinct purpose. The coarse aggregate serves as the filler, while the fine aggregate fills the gaps between the coarse aggregate.
Cement and water combine to create a binder. Cement paste, fines, and admixtures contribute to mixture mobility.
Steps of Concrete Manufacturing Process
The quality of hardened concrete largely depends on the level of attention given at each production stage. A critical aspect of concrete production is the proper distribution of elements in the mix design. Still, even this does not guarantee that the ultimate goal of producing high-quality concrete will be achieved.
Quality control ensures concrete is produced with consistent strength from batch to batch. To achieve this, some principles must be followed during the different concrete production stages.
Concrete-making steps include:
1. Material batching or measurement
2. Mixing
3. Transportation
4. Putting
5. Compressing
6. Treatment
7. Concluding
Let’s understand each one by one.
1. Materials Batching
Proper and accurate amounts of each ingredient should be utilised to produce high-quality concrete. Measure the aggregates, cement, and water with a 3% accuracy of the batch quantity and the admixtures with a 5% accuracy of the batch quantity.
Volume batching and weight batching are the two most common methods of batching materials. The size of the task, the needed production rate, and the required criteria for batching performance are the elements influencing the choice of batching method. It is advised to weigh batches of the most important works.
2. Mixing
Concrete can be mixed by hand, in a fixed mixer, or transported, depending on the type and quantity required for a given job. Whatever method is used to mix the concrete must be homogeneous in colour and consistent for the maximum setting.
Again, using shovels and other mixing instruments and manually mixing cement can tax workers' hands, necessitating a robust, durable glove for increased protection.
- Hand Mixing
- Machine Mixing
- Tilting mixers
- Non-tilting mixers
- Reversing drum mixer
- Pan-type or stirring mixer
- Transit mixer
3. Transportation
Concrete is transported using various techniques, including wheelbarrow and hand hauling, conveyor belt operations, and more complex projects, including cranes and pumps. All of these techniques required some level of manual labour and sophisticated protective gear.
Companies must make sure their gloves match safety criteria for anything from physically moving wheelbarrows to operating and securing large types of machinery and equipment moving concrete.
Concrete should be carried to where it will be deposited as soon as possible without losing the homogeneity achieved during mixing. If trucks with agitators are used to carry concrete, a maximum of 2 hours from the time of mixing is allowed; if trucks without agitators are used, a maximum of 1 hour is allowed.
Moreover, segregation should be avoided during installation and transit. The scope and importance of the project determine the methods used for carrying concrete. They are also determined by the distance between the mixing and dumping sites and the terrain's characteristics.
These are a few techniques for moving concrete:
- Mortar Pan
- Wheel Barrow
- Chutes
- Dumper
- Bucket and Ropeway
- Belt conveyor
- Skip and Hoist
- Pumping.
4. Compacting and Placing
Concrete must be placed with the utmost care to ensure homogeneity during mixing and prevent segregation during transportation. Research shows that delaying concrete placement increases its ultimate compressive strength if sufficiently compacted.
While a delay of up to an hour is permitted for dry mixtures in hot weather, it could take several hours for wet mixtures in cold weather.
5. Mass Concrete Pouring
When mass-laying concrete, such as a raft foundation, dam, bridge, or pier, 350-450 mm-thick layers are arranged in rapid succession to create a lift. Before pouring concrete into the next lift, the surface of the preceding lift is cleaned using water jets and wire-bristled scrubbers, and Sandblasting is done in the case of dams.
After removing any laitance and loose objects, cement slurry is applied. Bond bars or bond stones provide a key between several layers when the concrete is subjected to lateral thrust.
Concrete is laid out in bays for highways, runways, or floor slabs. The ground where the concrete will be placed must first be prepared by clearing it of all loose debris, grass, and other vegetation. The soil is saturated and pressed down.
To prevent any moisture loss from the concrete, the subgrades over which it is to be poured should be thoroughly compacted and dampened. Afterwards, concrete is placed between each bay. This enables the concrete to shrink sufficiently and prevents the subsequent development of cracks.
Concrete is poured at a consistent thickness rather than piled up and pulled.
6. Compaction
The process of producing concrete continues with concrete's compression after it has been placed in the intended area. Fresh concrete is consolidated by compaction around embedded components, reinforcement steel, and moulds or frames. A substantial amount of air is trapped in concrete during manufacture, and partial segregation is also conceivable.
Both harm concrete quality. Concrete must be compacted to eliminate trapped air and voids, stop segregation, and create a uniform, dense mass. It has been determined that 5% of vacancies in hardened concrete diminish strength by more than 30%, while 10% of spaces reduce strength by more than 50%.
Compaction is achieved by imparting external work over the concrete to overcome the internal friction between the particles forming the concrete, between concrete and reinforcement and between concrete and forms and by reducing the air voids to a minimum.
The following methods can achieve the compaction of concrete:
-
Hand Compaction
-
Compaction by Vibration
-
Needle Vibrator
-
Formwork Vibrator
-
Compaction by Spinning
-
Compaction by Jolting
-
Compaction by Rolling
7. Curing
The chemical reaction between cement and water gives cement strength and hardness. Moisture, an ideal temperature, and a length of time are known as the curing period. Curing newly put concrete is crucial. The clinker combination of C3S and C2S contributes significantly to the strength during the early phase, which takes around three weeks to complete.
The later power contribution from C2S is slow and takes a while. Concrete should therefore have access to enough water to enable it to reach its full strength.
Curing is the process of preserving moisture in concrete for this reason. The goal is to stop concrete from losing moisture due to providing more moisture or heat and moisture to hasten the process of strength gain, whether due to evaporation or another cause. At least three weeks and at least ten days must be spent curing.
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Methods of Curing
Several methods are used to cure concrete during the manufacturing process. Curing aims to ensure that the concrete reaches its maximum strength and durability potential and prevents it from getting moist.
Following are some of the prevalent methods of curing.
1. Water Curing:
This is the most common method used to cure concrete. Water is applied to the concrete surface to prevent moisture loss, typically by spraying or ponding. This method is effective in hot weather or dry climates with rapid moisture loss.
2. Steam Curing:
The concrete is cured by exposing it to high temperatures and steam in this method. Steam curing accelerates the concrete's strength gain, which reduces the curing time.
3. Curing by Infra-Red Radiation:
This method commonly produces aerated concrete. The concrete is cured in an autoclave, which uses steam and high pressure to accelerate the curing process.
4. Electrical Curing:
This is a relatively new curing method involving using a membrane to cover the surface of the concrete. The membrane prevents moisture loss and provides a stable environment for the concrete to cure.
5. Chemical Curing:
This method involves using chemical compounds to accelerate the curing process. This method is often used in precast concrete manufacturing.
Concrete Finishing
Concrete is basically used because of its high compressive strength. However, the finish of the ultimate product is not that pleasant.
Finishing in the concrete manufacturing process refers to the final steps taken to achieve the desired surface texture, appearance, and durability of the concrete. Finishing is crucial because it can significantly affect the concrete's strength, durability, and overall appearance.
- Formwork Finishes
- Surface Treatments
- Applied Finishes
The specific finishing techniques will depend on the desired look and function of the concrete. Proper finishing can ensure the longevity and performance of the concrete.
Also Read: How Do You Manufacture AAC Blocks?
Conclusion
This article details the process of manufacturing concrete and fundamental concepts like the manufacturing process of concrete making. The concreting steps towards doing the concrete business are the basic and foremost requirement for initiating this field of expanding one’s roots in the concrete business.
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