The need for TMT bars or Thermo-mechanically treated bars is rising every day. These are useful for the construction of best kind of enforced structures and can ensure long lasting construction projects. In order to ensure the best quality of TMT bars for your project, you can conduct certain tests in order to determine the strength of the Steel bars.
Types of Strength Tests for TMT Bars
There are various types of tests to determine the strength and elongation of TMT bars as per the BIS Code IS 1786. These include:
Universal Testing Machine (UTM) is used for testing the strength of steel reinforcement bars. Tensile Strength of all dia TMT bars can be tested in UTM as per IS 1786.
Yield Stress Test
Also known as 0.2% Proof Stress, it can be used to find out how much stress the material can take and exactly at which point it would begin to get deformed.It will elastically deform until the material gets to the yield point. Upon the removal of the applied stress, it will get back to its original shape.
Bend & Rebend Test
In this test, you have to bend the bar at 180°. Then, you need to check how the rebar behaves or responds to that stress. Ideally, it should not rupture or break. While doing the bending, proper Mandrel should be used as per IS 1786.
In a Rebend Test, you have to bend the bar at 135°. There should not be any crack while bending. Also, put the bar for 30 minutesin 100°C hot water. Then, you have to bend the bar at 157.5°. Check how the rebar behaves to that stress. There should not be any crack formation while re-bending.
Chemical Analysis Test
A sample should be cut from the length of the bar and one side needs to be used for testing in a spectrometer, for chemical composition. Just 10 to 15 seconds is taken by the spectrometer in order to produce results in a printed format, and you can find out about up to 26 elements in the bar. You can get the results of the percentages ofphosphorus, sulphur and carbon, which happen to be essential elements according to the BIS. A spectrometer also shows the percentages ofmanganese, copper, chromium etc when micro alloyed grade TMT bars are tested.