Concrete is an important construction material that is basically a chemical compound. This is prepared by mixing stone chips, cement, sand and water in a very specific proportion that hardens over time.
How Concrete Is Prepared for Civil Construction?
Most common concrete is made as a heterogeneous mixture of paste, aggregates or dolerite rocks chips and coarse or fine sands. The paste comprises of Portland cement and water. Two sizes of aggregates are normally used, one is coarse means larger chips and other is finer chips. The components are mixed intimately in an equipment called Mixer in batches. It is a hollow drum-like shape inside fixed with curved blades for the purpose of homogeneous mixing. The drum is rotary one by means of DG set for rotation of the drum. Through a chemical hydration, the paste gets harden and gains great rock like compressive strength to form a mass known as concrete. Sometime vibrator is used for proper distribution of green concrete material all over the casting slab.
The concrete making process is the key to a remarkable transformation of property within a short time interval. It is plastic and malleable when newly mixed and becomes strong and durable when hardened. These qualities are the key factors that explain why a single material like concrete, can build high rises, flyovers, airstrips, bridges, sidewalks, and superhighways, and dams.
The key factor for making a strong, durable concrete depends primarily on careful proportioning and mixing of the ingredients. A concrete mix should have enough paste to fill all the voids between the aggregates. Portland cement is activated in the presence of water. Cement and water form a paste that is very important and should coat each particle of stone sand and aggregates. A chemical reaction called hydration takes place during mixing. This reaction, make cement paste harden and gains strength which is called curing of concrete.
Typically, the concrete mix has a composition at about 10 to 15 percent cement, 60 to 75 percent aggregate and 15 to 20 percent water.
Steel Reinforced Concrete R.C.C
Since the compressive strength of concrete is more than tensile strength, steel rod cages are used. The steel cage design varies from application to application. Reinforced concrete is applied for high rise buildings, fly over, bridges and road which are subjected to vibration due to traffic movement.
The size of the mixing machine depends upon the volume of construction. If demand is big and rapid, truck mounted concrete pump and high capacity continuous mixer are employed.
Demand for Concrete
In view of the rapid growth of the infrastructure sector, a great number of roads, bridges, high ways, flyovers and multi-storey housing complex, shopping malls are under construction or planning stage. Expansion projects which are under construction include the airport, seaport, railway tracks and many more. Sky reaching the demand for concrete and reinforced concrete is been observed with the development of infrastructure.
Applications and Uses
- It is an important building material, and superior to wood.
- It is durable as well as cost-effective material which is most suitable for underground construction like metro tunnels, cable ducts etc.
- Concrete is an extensive and sustainable choice for residential and commercial projects.
- The strength of concrete develops with curing time.
- Its benefits weather protection and have minimum maintenance.
- It is budget friendly and can be used anywhere.
- Its buildings can be designed as earthquake proof which is safe for building occupants.
- It is an inert material and neither burns nor supports combustion.
- Concrete can be produced from locally available materials and has a minimal environmental impact.
- Concrete can be cast into various shapes when freshly mixed.
- Concrete increases construction life.
- It keeps home free from insects.
- It has multiple design possibilities.
- Concrete is able to withstand steel reinforcements, loads of gates, tunnel lines, electrical cable structures.
Overall it can be mentioned that importance and demand for concrete is remarkable and growing extensively with the growth of the infrastructure sector.
October 31, 2018
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