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RE: corrosion of cor-ten type rebars

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Prakash,

I just completed some research on embedded weathering steel in concrete
recently.  Unfortunately the project and exact nature of the application is
classified.  In the 1960's there was an effort to use weathering steel as
rebar by a rebar manufacturer, since the results were negative the
initiative was abandoned, and the research was never published.  Treadway's
research is the only published information that I am aware of.

Your ultimate conclusion is correct.  It should not be used in concrete.


Regards,
Harold Sprague


> -----Original Message-----
> From:	prakash chowdhury [SMTP:pcchowdhury(--nospam--at)yahoo.com]
> Sent:	Monday, August 14, 2000 1:05 AM
> To:	seaint(--nospam--at)seaint.org
> Cc:	SpragueHO(--nospam--at)bv.com
> Subject:	corrosion of  cor-ten type rebars
> 
>  
> 
> 1.	I will be grateful to receive any data/opinions/references on the
> performance of corten- type weathering steels embedded in concrete (with
> or without chloride contamination). Until ca.1989 the consensus was
> clearly negative but news of more recent developments would be welcome.
> 2.	ACI Committee 222, in its Publ. 222 R-89 (Corrosion of Metals in
> Concrete), pronounced such steels as "not suitable for reinforcement"
> since embeddment in concrete deprives the steel of the very exposure to
> atmosphere that is esential for the development of the corrosion resisting
> dense oxide film.
> 3.	The Building Research Establishment (BRE,U.K.) conducted long-term
> exposure tests of such weathering steels in concrete and reported
> (Durability of Corrosion Resisting Steels in Concrete by Treadway et
> al.,Proc.I.C.E. Part 1,1989) :
> 
> a.	for low levels of chloride contamination, weathering steels do not
> improve durability and hence do not justify the additional costs, and
> b.	for high levels of chloride contamination, pitting corrosion was
> sufficiently severe to indicate that weathering steels would be
> unsuitable.
> 
> 4. In spite of such consistently negative recommendations (based on both
> theory and experiments), such steels are being specified for RC structures
> in India based mainly on manufacturers' claims of their superior corrosion
> resistance in concrete. Any feedback from international sources would
> greatly benefit the evolvement of a consensus among civil engineering
> consultants and clients.
> 
> 
> 
> ******************************************************************
> 
> Prakash C. Chowdhury, B.Sc.(Surrey), Ph.D.(N'cle)                       
> 
> Regional Resident Representative  
> 
> Torsteel Research Foundation 
> 
> H-1A, Hauz Khas 
> 
> New Delhi - 110 016, India 
> 
> E-mail : pcchowdhury(--nospam--at)yahoo.com <mailto:pcchowdhury(--nospam--at)yahoo.com>
> 
> 


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