Differing Mtls Corrosion examples

[zcp]

I seem to get more and more architects that want to copper clad aluminum structures or set aluminum posts in concrete. Does anyone have any corrosion horror stories or pictures they would like to share from the world of construction? Examples of requested materials that made you chuckle (or wince) would be nice too.

ZCP

http://www.phoenix-engineer.com

 

[civilperson]

A concrete extention chute made in the shop of folded aluminum for ease of handling on a ready mixed delivery truck. Consistent low breaks when three chutes used compared to two chutes(steel).

 

[apsix]

civilperson, I was suprised by your claim, so I did a google and found that it is a recognised problem.

From

http://www.aci-int.org/FAQ/afmviewfaq.asp?faqid=66

"In the early days of concrete pumping, concrete pumped through aluminum pipelines abraded the metal, which then reacted with calcium hydroxide to produce enough hydrogen bubbles to significantly reduce concrete strength. Because of this problem, ACI 301-05, “Specifications for Structural Concrete,” forbids the use aluminum pipes or chutes for conveying concrete."

 

[dbuzz]

Do not set aluminium posts in concrete.

See thread507-88002 for a good explanation of how aluminium interacts with concrete.