Important properties of reinforcing steel bars
Steel Reinforcement is very vital material of Reinforced Concrete Structure. Steel is the ideal match for reinforced concrete structures that is designed with the key point that the steel and concrete function jointly to resist the operative force on RC structure.
The characteristics of thermal expansion for steel and concrete are almost equivalent upto a extremely high temperature together with this steel containing its outstanding bendability property and strong enough to resist tensile load to fulfill the shortcoming of concrete to meet tensile load.
In normal concrete structures, the steel bars applied as reinforcement are called rebars. In pre-stressed concrete structures, the reinforcement (steel wires) are stressed before exposing the structure to loading that may be considered as active reinforcement.
Given below, some crucial properties of rebars :-
The standard quality rebars can be selected based on the following properties :-
Sound strength for creating cost-effective design of RCC structure.
1. Good gripping with concrete i.e. good bonding.
2. Thermal expansion properties well suited with concrete.
3. Good ductility to resist cyclic loading (as for instance earthquake loading) or impact.
4. Good bendability necessary for providing necessary shape to rebars to satisfy the demand of the structures.
5. Good weldability for simplifying the process of good reinforcement cage binding and saving of lap length.
6. Good resistance against corrosion for greater longevity of R.C. structure.
Manufacturing process of high strength rebars :-
1. Generally two routes are allows for manufacturing of steel (mainly in India).
2. Primary steel making route : Under this system, the billets rerolled to build up rebars are formed as follow :-
3. This route facilitates greater chemical composition and physical characteristics of steel. The targeted characteristic can be attained.
4. It can be arranged in bigger steel plants with facilities mentioned above.
Secondary steel making route : Under this system, the rebars are produced from rerollable pencil ingots made of scrap steel materials like scrap rails, automobile scarp, defense scrap, scrap produced from ship braking or discarded structures etc.
According to CI. ? 1.6 of IS : 1786 (2008) rebars developed through this route is not recognized since the metallurgical history is not completely documented or unknown.