jar546
Forum Coordinator
Here is a great video that not only discusses the name of the thread but goes on to other rebar related issues.
One reason that the codes do not recognize the non steel reinforcing is that they do not have the ductility of steel rebar. If rebar has proper anchorage it does not fail when the yield strength is reached. Instead the rebar continues to stretch.
The pictures of the failed test specimens show that the rebar was not properly anchored. In a properly anchored beam where the rebar was allowed to yield you would see a different cracking pattern.
Yielding serves several purposes.
A beam or slab that does not have ductile reinforcing is likely to fail suddenly when over loaded while ductile reinforcing will allow the member to deflect noticeably thus allowing people to take action before failure.
Ductile rebar and ties will allow compression members such as columns to resist severe overloads thus preventing catastrophic failures even if the member is severely damaged.
When designing to resist earthquake loads the yielding of the rebar is used to dissipate energy and allow the structure to survive without collapsing.
The point is that you should follow the code requirements that require the use of steel rebar.
Corrosion is a concern but experience has show that under normal circumstances corrosion can be managed and the members can have a long life.
Rebar with rust should not be rejected if the rust is tight and if there is no reduction in cross sectional area.