TMT Rebar in RCC construction
RCC Construction cannot be completed without Best Quality TMT Bars. TMT Bars provide strength in Reinforced Cement Concrete and makes every structure long lasting.
What is RCC Construction?
Francois Coignet, a French industrialist built a four storey house in Paris with reinforced cement concrete in 1853. That was first ever attempting to build using reinforced cement concrete in modern history. Since then, the technology has evolved with one of the highest buildings in the world being built using RCC.
Reinforced Cement Concrete is a composite material with excellent strength and durability. Like clay, concrete can be moulded into any shape, on any scale by using suitable moulds or formworks. One can make concrete anywhere by mixing its components in suitable proportion. It slowly develops strength over a period of time, which helps in smooth onsite operations. This portable nature of concrete along with the strength it develops is the key to its popularity.
Introduction of TMT rebar in RCC Construction
Concrete on its own has got excellent strength when pressed against anything. However on pulling (or stretching) it easily gives way.
While concrete has been used as a construction material since Roman times, the use of reinforcement in the form of iron was only introduced in the 1850’s by Coignet, and it was not until the 1880’s that a German civil engineer G. A. Wayss used steel as reinforcement.
Steel round that has prominent grips are forcibly inserted in concrete to give desired strength. Beauty of steel rebar is that they can take both extensible as well as compressive loads. In RCC columns you would find steel rebars carrying bulk of compressive loads. Steel & concrete have got similar temperature coefficients, making them expand/contract together and helping the bonding.
The introduction of Thermo Mechanically treated (TMT) steel bar has brought a new era in India’s construction industry. Round plain steel ruled over this industry up to sixties. TOR steel took over in the seventies and maintained its supremacy till nineties. 1997 Onwards the industry has seen extensive use of TMT steel bar that are corrosion-resistant, thereby ensuring longer life for RCC structures. TMT bars are widely used in general concrete reinforcement structures, bridges and flyovers, dams, thermal and hydel power plants, industrial structures, high-rise buildings, underground platforms in metro railway and rapid transport system.
TMT is an acronym for “thermo-mechanical treatment”. Thermo Mechanically Treated (TMT) bars are manufactured using the Quenching & Tempering (Q & T) technology. A TMT bar gets its strength properties from quenching and tempering. No mechanical treatment is involved in TMT Bars.
In TMT bars, the carbon content can be restricted to 0.25% to attain weld-ability and at the same time no strength is lost on this account. The joints can be welded by ordinary electrodes and no extra precautions are required. Another advantage of TMT bars is their tough surface providing high yield strength and a soft core providing excellent ductility. Strength, weldability and ductility are the properties which make TMT steel highly economical and safe. An additional advantage of TMT steel is that a twisting operation is included in Tor steel, which subjects the bars to torsional stresses making them less corrosion resistant while TMT bars are free of such stresses. As a result TMT bars have excellent corrosion resistance power. There are ample of TMT Bar Manufacturers in the market but it is always required to buy ISO Certified TMT Bars that has the perfect combination of Strength & Flexibility.
The TMT process gives the bar superior strength and anti-corrosive properties. Controlled water-cooling prevents the formation of harsh carbides, which is the main reason behind the corrosive nature of common bars. Due to very high elongation values and consistent properties throughout the length of bar, TMT rebars have excellent bendability. The soft ferrite pearlite core enables the bar to bear dynamic and seismic loading. TMT bars have high fatigue resistance to dynamic / seismic loads due to its higher ductility. This makes them most suitable for use in earthquake prone areas and very cost effective.
QUANTITY OF STEEL USED IN RCC CONSTRUCTION
- FOR RCC SLAB: 1.0% OF CONCRETE VOLUME
- FOR RCCBEAM: 2.0% OF CONCRETE VOLUME
- FOR RCC COLUMN: 2.5% OF CONCRETE VOLUME
- FOR RCC ROAD: 0.6% OF CONCRETE VOLUME
CONSTRUCTION COST and REBAR COST PER SQ. FT OF BUILT-UP AREA
- LIG (G+4): CONST. COST = RS. 1500/- / SFT & REBAR COST + RS. 150/- / SFT
- MIG (G+7): CONST. COST = RS. 1900/- / SFT & REBAR COST + RS. 180/- / SFT
- HIG (B+G+10): CONST. COST = RS. 2300/- / SFT & REBAR COST + RS. 240/- / SFT
- COMMERCIAL (B+G+10): CONST. COST = RS. 2900/- / SFT &
REBAR COST + RS. 300/- / SFT
Advantages of Using Rebars in RCC Work
- To increase its overall strength, TMT Steel bars, wires, mesh or cables can be embedded in concrete before it sets. This reinforcement, often known as rebar, resists tensile forces. By forming a strong bond together, the two materials are able to resist a variety of applied forces, effectively acting as a single structural element
- Reinforced concrete can be precast or cast-in-place (in situ) concrete and is used in a wide range of applications such as slab, wall, beam, column, foundation, and frame construction. Reinforcement is generally placed in areas of the concrete that are likely to be subjected to tension, such as the lower portion of beams. It is usual for there to be a minimum of 50 mm cover, both above and below the steel reinforcement, to resist spalling and corrosion which can lead to structural instability
Checklist for Steel Reinforcement
- Should be free of loose rust, oil paints, mud, dust, etc
- Should be stacked above the ground level free from any water accumulation
- Should be cut, bent (preferably by cutting & bending machines) and fixed properly by using right size of binding wires at required intervals
- Should be fixed in a position by use of cover blocks (if it is concrete cover block then grade of concrete should be the same or higher), chairs, spacers, additional supporting bars, and laps; laps to be used in proper location as advised by Engineer-in-charge.
- Should be placed and tied in such a manner that concrete pouring is done without any kind of segregation and compaction is done by an immersion vibrator of right size as per the requirement
It is always
important to buy from Best Quality TMT Bar Manufacturers. India’s most of the
places such as West Bengal, Bihar, Assam etc. come under high seismic zone. As
per IS Standards Fe500d
grade TMT Bar has the perfect combination of Strength & Flexibility.