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Material Testing

Rebend Test of Rebar

A ductility check that bends the bar, holds it in boiling water, then bends it partly back — any crack on the outside of the bend means the steel fails.

Constropedia Editorial First published January 2022 · Updated September 2026 · 2 min read

Objective and Significance

This test method is used for evaluating ductility. Unless otherwise specified it shall be permissible to age bend test specimen. The time-temperature cycle employed must be such that the effects of previous processing will not be materially changed. It may be accomplished by aging at room temperature 24 to 48h.

Rebend test reference in the app Steel BBS Calculator A1 Pro has rebar test references — tensile, rebend, bend, bond and fatigue — each with a generated report.
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Aim

Aim of this test is to determine Rebending capacity of the reinforcing Bar.

Apparatus

Bar Bending Machine: This Machine is used to bend the bar.

Procedure

  • First bend the bar to an included angle of 135°.
  • Keep it in boiling water at 100 °C for 30 minutes.
  • Then cool it down for some time.
  • After cooling, bend it back to an included angle of 157.5°.
  • The rebar should not show any rupture or cracks visible to a person with normal or corrected vision.
Diagram of a bar bent around a pin, with two raised lines marking the 135° first bend and the 157.5° rebend
  • While applying load on the sample bar it is important to ensure that the load is uniform, smooth and vertically downwards. Impulse load should be avoided.
  • After getting satisfactory results, you can approve the steel for further usage in actual construction.

Result

If the Rebending around the pin could be done without cracking on the outside of the bent portion the result is ‘satisfactory’. If cracking was found on the outside of the bent portion, it would be considered that the rod did not meet the bending requirements and the result is ‘unsatisfactory’.

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