Key Points of Material Technology in Precast Production
Precast productions are done by giving the material the desired shape and design, and then, in accordance, when the concrete hardens, it is attached to the structure.
In this process, the required structure is first manufactured inside the factory and then it is transferred to the construction site for attachment to the structure.
This method is very suitable and ideal as it helps save time and is beneficial in the case of construction in congested localities where there isn’t much adequate space to build the structure.
The pre-casting is done by mixing various materials like cement, water & fine stone aggregates.
The precast finished material also known as cured concrete product is used in high-rise buildings, flyovers, highways, industrial premises, and commercial buildings. Etc.
Precast concrete has its own challenges as well. Moving precast concrete is a bit challenging since it requires a large area for the conveyance of precast material.
It helps in saving time at the construction site as the precast material is easy to install and is easy to assemble at the site.
The following are the points for understanding the concrete material technology in precast production:
Concrete is the key component of the precast production:
The precast product visual surface quality of the concrete mix being used comes primarily. The load-bearing capacity of the structure depends upon the concrete mix.
The environmental factor is also crucial in the use of concrete as it causes damage to the environment.
Thus, proper utilization of concrete is essential for precast production:
- The concrete mix design should be cost-effective. It should not be too expensive.
- Strength appropriate to the design and any other requirement.
- Fast and controlled hardening.
- Appropriate workability according to the casting method.
- Better durability according to design requirements.
- Also, the environmental factors need to be kept in mind.
Quality control on raw materials:
The use of aggregates is essential for the precast of the concrete. Fine gravel or stone aggregates are added to the concrete, usually, for the purpose of enhancing the strength of the concrete.
Aggregates are one of the stable components in concrete and thus help in framing the concrete. Cement is used as the glue for holding aggregate particles together.
In the precast concrete, the volume of the aggregates should be increased, and the amount of water and cement should be reduced.
The focus should be on the quality of the aggregates rather than the cement as the quality of the aggregates varies largely and its properties as well.
Cement is the key component:
Cement consists of the major cost of the material in the concrete mix. Its properties usually depend upon the type of cement and impact directly on the concrete properties.
The cement factories give the major information about the cement to be used. The cost can be reduced with the help of different binders and the quality of the concrete can be improved and can also reduce the environmental impact on the concrete.
In the case of precast concrete, early setting of the concrete is a necessary requirement. The curing needs to be done and is an essential part of the precast concrete process.
Admixtures and additives are an important part of concrete technology:
Admixtures are added to the cement concrete during the mixing of the concrete. Their dosage is decided based on the cement content.
The concrete admixtures may have a chemical or physical nature, and it has a significant impact on the hardening process of the concrete.
Concrete admixtures can have a significant impact on the quality of concrete thus due to that the quality of concrete must be checked.
Various plasticizers are common admixtures in precast factories. Plasticizers are added either to raise the strength of concrete or to enhance the flow of concrete without any supplementary use of water into the concrete.
Additives may be inactive or active. Generally, the most common inactive additives are lime fillers, rock flours, and color pigments.
The water requirement increases in the case of the use of powdered limestone. Limestone is generally used in self-compacting concrete.
Active pozzolanic or latent hydraulic materials like fly ash or content silica fumes, ground granulated blast furnace slag, are used to improve concrete properties or else reduce the mixing cost.
The curing process and maturity control are important phases of production:
In concrete, the result of the reaction with water equals the strength gained by the concrete. The hydration reaction increases the heat inside the concrete. The reaction can be made even faster by supplying external heat to the concrete.
In the presence of heat-based curing, early development can be controlled. The maximum temperature recommended for concrete is 60 degrees Celsius with a per-hour increase of 25 degrees in temperature.
In case there is a temperature difference of more than 20 degrees centigrade between the surface and interior of the product then in that case the concrete may be caused by cracks inside it.
To gain consistent and constant quality of the concrete right way of curing is essential.
The curing measures are as follows:
- Protection from generally adverse climatic influences.
- Use a curing agent.
- Cover with sheets or frost blankets.
- Should be kept damp/mist if required.
- The curing time should be relevant to the temperature.
Conclusion:
Thus, we learned about the material technology in precast production in depth. Precast production is essential as it helps save space at the site and makes it easy for the workers to assemble the joints that are pre-cast.
Concrete is an essential part of pre-cast production, while the other factors include controlling raw materials, using key components as cement in pre-casting, use of admixtures and additives, curing process, and additive control.
Having proper knowledge of concrete technology is essential before working on successful precast operations. The admixtures and additives along with aggregates help in increasing the strength of the concrete.