What is RCC Building in Construction?
Due to their strength, resilience, affordability, and numerous other appealing qualities, RCC structures have become the most popular trend in India’s construction industry. Reinforced Concrete is a term used to describe a mixture of concrete and steel reinforcement that is cast into a single piece and functions as a monolithic element. Due to their complementary qualities, concrete and reinforcement are combined to form the fundamental component of construction. Reinforced concrete can withstand both tensile and compressive loads exerted on the structure because concrete is weak in tension and strong in compression whereas steel is weak in tension and strong in compression. Steel helps the structure withstand tensile stresses due to its extremely high ultimate tensile strength.
Because the concrete sticks securely to the steel rods during curing and protects them from corrosion, the combination of concrete and steel is particularly successful. Hydration of the cement creates an alkaline medium. They both have almost the same coefficient of linear expansion, which contributes to their monolithic behaviour. Additionally, both of these materials’ physical and mechanical characteristics are unaffected by temperature changes between a range of -40°C and 60°C, allowing for application in nearly all climatic locations.
Frequently utilised Reinforced Concrete
RCC concrete has undergone substantial improvement in the last several decades due to the need for strength and endurance in the face of various conditions. New reinforced concrete materials have emerged as a result of these innovations, including fibre-reinforced concrete (FRC), carbon concrete, autoclaved concrete, lightweight reinforced concrete, high-performance concrete, etc.
Following are the three types of reinforced concrete that are most frequently used:
- Fibre-reinforced Concrete: Fibre-reinforced concrete is mostly used in contemporary structures and pavement toppings. This type of reinforced concrete uses biological, mineral, and steel strands as its fibres. Each section of concrete constructed using FRC has equal tensile strength. Using steel fibres or other fibres as reinforcement rather than steel rods lowers the overall cost as well.
- Polymer Concrete: This type of concrete is created by completely swapping out the cement hydrate binders used in traditional cement concrete for polymer binders. It outperforms regular cement concrete in terms of strength, adhesion, chemical and abrasion resistance, etc. At room temperature, the polymerization of binders results in the hardening of polymeric concrete.
- Ferrocement Concrete: Wire meshes and cement mortar are combined to create ferrocement concrete. It is lightweight reinforced concrete that is incredibly adaptable and can be formed into any shape needed. It is favoured due to qualities like ease of construction, cheap material costs, durability, improved resistance to earthquakes, etc.
Advantages of RCC
- Comparatively speaking, reinforced concrete outperforms other building materials in terms of compressive and tensile strength.
- RCC structures are more resilient than other structures.
- Before the mix hardens, reinforced concrete can be moulded into any shape.
- RCC structures are durable and require little upkeep.
- Compared to the construction of steel structures, RCC buildings require less skilled people.
- The structural integrity of RCC can survive exceptionally high fire temperatures for a longer period of time.
- Cast-in-place reinforced concrete buildings are strong enough to withstand gusts of more than 200 mph and perform well even when struck by flying debris.
- In order to comply with strict fire rules, concrete performs well in both natural and man-made disasters and doesn’t require any further fireproofing treatments.
Disadvantages of RCC
- Only about a tenth of the compressive strength of reinforced concrete is available as tensile strength.
- There are various phases involved in building with RCC, such as mixing, casting, and curing. The final strength of the RCC may alter if any of these procedures are skipped or improperly carried out.
- Correct and sufficient compaction must be performed. Fewer strengths result from less compaction and vibration. Heavy vibration results in the segregation and bleeding of concrete.
- After hardening, shrinkage in RCC structures can lead to the development of cracks and a loss of strength.
Steel Reinforcement used in RCC Concrete:
In concrete constructions, there are primarily four types of steel reinforcement utilised during construction:
Hot Rolled Deformed Bars:
This type of reinforcement is most common for standard RCC buildings. Hot rolling, which involves surface deformations like ribs, is done in the mills. This process aids in forging a link with the concrete. There is a distinct yield point on the stress-strain curve, which is followed by a plastic phase in which the stress remains constant but the strain grows.
Cold Twisted Deformed Bars:
Cold-worked reinforcement is produced when a hot-rolled steel bar is subjected to the cold-working process. At room temperature, the bars are twisted or drawn using the cold working technique. This essentially removes the Plastic Stage from the Stress-Strain curve even if it gives the user more discretion over bar size and tolerances. These bars are less ductile than hot-rolled bars since the plastic stage was removed. These kinds of bars are only used in projects where low tolerances and straightness are crucial considerations.
Thermo-mechanically treated reinforcement bars are referred to as TMT Bars. These bars can produce steel bars with high strength at the surface and a mild steel core by abruptly cooling red hot steel bars with a water spray. TMT bars are also constructed with ribs (rebars) to strengthen the bonds between the bars. TMT bars get their corrosion resistance property from the addition of corrosion-resistant materials including copper, phosphorous, and chromium.
TMT bars are highly recommended for use in reinforced concrete constructions because they are more corrosion-resistant than Tor Steel.
Prestressing Steel Bars:
It is applied as tendons or bars, which are often formed of several strands. However, because they may be laid in different profiles, which is a key criterion of prestressing steel, these tendons/strands are more frequently used. Prestressing strands are made up of many wires, usually 2, 3, or 7. For use in construction, these wires, which are typically cold-drawn, have a high tensile ultimate strength.