Acceptable amount of rust on rebar 2

[CTW]

I wanted to get some opions from others as to how much rust would be acceptable on rebar. I've got a project that was stopped for about 9 months and the rebar had been fabricated but left exposed to weather at the site. There does not appear to be any flaking or scaling. The application is mainly foundations for vertical storage tanks where the reinforcing is for shrinkage and temperature.

 

[hokie66]

Based on your description, I wouldn't consider the rust as a problem.

 

[SlideRuleEra]

I concur with hokie66. Here is a definitive statement on this subject from the Concrete Reinforcing Steel Institute (see the last question)

http://www.crsi.org/rebar/faqs.html

http://www.SlideRuleEra.net

 

[lexim]

Hi CTW ,

There is no issue to worry about on your rebar state. Thanks SlideRuleEra for the link.

 

[civeng80]

rare for rebar not to have rust. Probably a good thing since it helps the bond between concrete and steel. If its flaking rust then I would reconsider!

 

[CTW]

Thanks for your responses.

 

[vincentpa]

Read 7.4.2 ACI 318. "Except for prestressing steel, stell reinforcement with rust, mill calse or a combination of both shall be considered satisfactory, provided the minimum dimensions and weight of a hand-brushed test specimen comply with applicable ASTM specifications referenced in 3.5" You can read the commentary for more information and the CRSI and PCA have more of an explanation as mentioned above. Rust is ok unless it is loose rust or section loss has occured.