Rebars Sever Corrosion Effects 5

[ALK2415]

What's your opinions on following lack of QC/QA control of major highway bridge ?
can you estimate actual reduction percentage of bearing capacity of these curved box girder ?
Is there a reliable testing method that could investigate the propagated corrosions among rebars ?
Can loading test (actual loaded trucks HS20-44) prevail "corrosion" and its effects on short terms structural performance

 

[LittleWheels]

Absolutely true. We do not allow the use of epoxy-coated rebar on our projects due to highly concentrated/ intensive corrosion at coating defects.

 

[dik]

...the accelerated corrosion at the damaged area causes more epoxy to fail. Concrete cover or HDG (depending on the cause of corrosion) is usually better.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[Compositepro]

Zinc will react with caustic cement like aluminum will.

 

[dik]

Yes a little... not anything like aluminum, though... not even close. HDG, along with the passivity provided by the high pH of the concrete, and increased concrete cover is often used for corrosion resistance.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[Cool_Controls]

Chrome rebar Link

 

[FacEngrPE]

Cathodic protection of rebar in concrete seems to be falling into favor. Link
Some approaches install passive anodes, others use active systems with external power supplies. Use of cathodic protection with painted rebar should be possible, but ensuring the electrical connectivity of the rebar and anodes would be a challenge.

https://www.wesavestructures.info/cathodic-protection

 

[LittleWheels]

Sacrificial anodes are the preferred option amongst our clients, mostly in ports and harbours. Few want to carry out the regular monitoring and maintenance necessary with impressed current systems, though I was involved with some extensive schemes with a highway authority years ago. Comprehensive cathodic protection of epoxy-coated rebar doesn't seem very easy to achieve/ practical.

 

[Keith_1]

As a Developer and VP of a GC I have installed nothing but hot dipped galvanized on exposed areas in coastal construction in South Florida, maintaining coatings goes a long way to prevent costly mediation. I have had subcontractors try to spray paint it with cold once or twice, they never did it more than once.

Most of these things are so simple to prevent it frustrates me, Millenium Tower was different, the GC, Foundation Co, Engineer and Architect should all lose their licenses, they bragged about saving a few million and a month of time, that is just someone that should not have a stamp or a license. At that level everyone should know what the appropriate Geotech work looks like.